What is the best image format for websites, WebP, JPEG, or PNG?

WebP is usually the best choice for websites. It produces files 25-35% smaller than JPEG at the same visual quality, supports transparency like PNG, and is supported by all modern browsers including Chrome, Firefox, Safari, and Edge. Use JPEG for photographs when WebP is not required. Use PNG only for images that need lossless quality or broad software compatibility.

How do I compress images to reduce file size without losing too much quality?

Select WebP as the output format and set quality to around 80%. WebP gives significantly smaller files than JPEG or PNG at equivalent visual quality. For photos, quality settings between 75 and 85% are usually a good balance. Use quality 85-90% if the image contains text or fine detail. Always check the file size savings badge that appears on each processed image card.

Can I convert images to black and white or grayscale in bulk?

Yes. In the Color filter section, click Grayscale (B&W). This removes all color information from every processed image, producing true black-and-white output. You can also select Sepia for a warm vintage brown tone. The filter is applied after resizing and rotating, so it works with any resize mode and output format.

Bulk Image Resizer & Converter

Q: Can I add a watermark to multiple images at once?

Yes. In the options panel, select Text watermark to add copyright text, or Logo / image to upload your brand logo. Set the position (top-left, top-right, bottom-left, bottom-right, or center), adjust the size, opacity, and margin, then process all images. Every image in the batch gets the watermark applied before download.

Q: What is the difference between Fit, Fill, and Crop resize modes?

Fit scales the image to fit inside your target dimensions while keeping its original aspect ratio. No padding is added, so the output may be smaller than the target box. Fill pads the image to exactly match your target dimensions using a background color you choose. Crop scales and center-crops the image so it covers the target dimensions exactly with no padding or empty space.

Q: How do I resize images for social media?

Click one of the social media presets: Instagram Post 1080x1080, Instagram Portrait 1080x1350, Instagram Story 1080x1920, YouTube Thumbnail 1280x720, X/Twitter Header 1500x500, Facebook Cover 820x312, LinkedIn Post 1200x1200, Pinterest Pin 1000x1500, or Open Graph 1200x630. The preset sets the correct dimensions and crop mode automatically.

Q: Can I convert PNG to JPEG in bulk?

Yes. Upload your PNG files, set the output format to JPEG, adjust the quality slider, and click Process All and Download ZIP. All PNG images convert to JPEG and download together. Note that JPEG does not support transparency; any transparent areas are filled with white by default.

TL;DR — drop images, pick a preset or mode, set format and quality, then download the ZIP.

6 resize modes, 9 social media presets, WebP/JPEG/PNG output, grayscale/sepia color filters, text and logo watermarks, rotate/flip, file size savings display, processed image preview, and custom filename templates. Everything runs in your browser. Nothing is uploaded, nothing is stored.

Free Bulk Image Resizer & Converter — Batch Resize, Convert, Watermark, and Filter Online

This free bulk image resizer lets you resize, convert, and process dozens of images in one pass without installing software or uploading files to a server. Upload your JPG, PNG, WebP, GIF, or AVIF images, configure your settings once, and click one button to process every file in the batch simultaneously. Download everything as a single ZIP file in seconds.

The tool goes beyond basic resizing. Choose from six resize modes including Fit within, Exact crop, Exact size with padding, Scale by percent, and Long edge normalization. Convert to WebP, JPEG, or PNG with a quality slider for precise size control. Apply a grayscale or sepia color filter, add a text or logo watermark with custom position and opacity, rotate or flip images, and customize output filenames with a template system. After processing, each image card shows the exact file size savings and a preview of the processed result.

Nine social media presets cover every major platform: Instagram Post, Portrait, and Story; YouTube Thumbnail; X / Twitter Header; Facebook Cover; LinkedIn Post; Pinterest Pin; and Open Graph. One click sets the exact pixel dimensions and selects the right crop mode automatically.

What is bulk image resizing and why does it matter?

Bulk image resizing is the process of changing the pixel dimensions of multiple image files in a single operation rather than editing them one by one. It matters for several reasons:

Page speed: Oversized images are one of the most common causes of slow websites. A product photo taken at 4000x3000 pixels served on a 400-pixel-wide card wastes bandwidth and hurts Core Web Vitals scores. Resizing images to their display dimensions reduces load times directly.
Storage costs: Smaller files consume less storage on hosting servers, CDNs, and cloud storage buckets. Bulk resizing a product catalog from 5 MB originals to 200 KB WebP thumbnails can reduce a 10 GB catalog to under 400 MB.
Platform requirements: Social media platforms, CMS tools, and email marketing systems enforce specific image dimensions. Uploading the wrong size can cause cropping, distortion, or rejection. Presets handle this automatically.
Consistency: Design systems and product catalogs require every image to be exactly the same size. Crop mode ensures pixel-perfect uniformity across a batch.

Advanced features that go beyond basic image resizing

Most online image resizers offer width and height inputs and a download button. This tool is built as a real batch processing tool with features that professional creators, e-commerce teams, and developers use every day.

Grayscale and sepia color filters

New

Convert color photos to black-and-white or add a warm vintage sepia tone to the entire batch in one step. The filter is applied using the standard luminance formula (0.299R + 0.587G + 0.114B for grayscale), so it produces accurate tonal output rather than a flat channel removal. Filters are applied after resizing and rotating, so you get pixel-accurate results at the final output dimensions. Works with any output format and any resize mode.

File size savings display

Insight

After processing, each image card shows the output dimensions, output file size, and a colored savings badge. A green badge shows how many percent smaller the processed file is compared to the original — for example, -58% saved when converting a large JPEG to WebP. An amber badge appears when the processed file is larger than the original, which can happen when converting a compressed JPEG to lossless PNG or when upscaling. This lets you quickly spot settings that are not working as expected without having to open a file manager.

Processed image preview (lightbox)

Visual

Once an image is processed, the thumbnail in the queue updates from the original to the processed result, so you can see exactly what will be downloaded. Hover over any thumbnail and click the zoom icon to open a full-size lightbox preview of either the original or the processed image. This lets you verify quality, crop alignment, watermark position, and filter output before downloading the ZIP, saving you time on large batches.

Social media presets

Presets

One-click presets for every major platform: Instagram Post, Portrait, and Story; YouTube Thumbnail; X / Twitter Header; Facebook Cover; LinkedIn Post; Pinterest Pin; and Open Graph 1200x630 for link previews. Each preset sets the exact pixel dimensions and selects the Exact crop mode so your images fill the frame without letterboxing. Presets are highlighted with a blue ring when active, and the dimensions update immediately in the options panel so you can adjust further if needed.

Text and logo watermarks

Branding

Add a branded copyright notice or upload a transparent PNG logo. For text watermarks, configure the font size, text color, opacity, and position. For logo watermarks, set the logo size as a percentage of image width so it scales proportionally regardless of image dimensions. Both watermark types support five positions (four corners and center), an adjustable margin in pixels, and opacity control from 10 to 100%. Watermarks are rendered after all other transforms so they always appear on the final output at the correct size and position.

Custom filename templates

Workflow

Name processed files exactly how your workflow needs them. The template system uses tokens: {name} for the original filename, {w} and {h} for output dimensions, {ext} for the format extension, and {i} for the sequence number. A template like product-{name}-{w}x{h}-{i}.{ext} produces structured, sortable filenames automatically. This is essential for e-commerce teams, content libraries, and any pipeline where consistent file naming is enforced.

How to use the bulk image resizer

Upload your images. Drag and drop files onto the upload area, or click to browse. You can add multiple files at once. The tool accepts JPG, PNG, WebP, GIF, BMP, and AVIF.
Choose a preset or resize mode. Click a social media preset to set exact platform dimensions instantly, or choose a resize mode and enter custom pixel values. Enable Lock aspect ratio if needed.
Set output format and quality. Choose WebP for web use, JPEG for photography, or PNG for lossless output. Adjust the quality slider (WebP 75-85% is a good starting point). Use the background color picker if you selected Fill mode.
Apply optional transforms and effects.Rotate or flip if your images are oriented incorrectly. Select a color filter for B&W or sepia output. Add a text or logo watermark with your preferred position and opacity.
Download individually or as a ZIP. Click Process All & Download ZIP for the entire batch, or use the per-image button to process and download a single file. Check the savings badge on each card to verify the output meets your size targets.

All 6 resize modes explained

Mode	What it does	Best for
Fit within	Scales the image to fit inside the target box while preserving aspect ratio. May be smaller than the target.	Portfolio galleries, article images, content where composition matters
Exact size (Fill / pad)	Scales to fit, then pads empty space with a background color to reach the exact target dimensions.	Hero banners, product cards requiring a fixed canvas
Exact crop (Cover)	Scales to cover the target box and center-crops any overflow. No padding, no empty space.	Thumbnails, social media posts, product grids needing consistent sizes
Scale by %	Scales all images by the same percentage relative to their original size.	Quick proportional downsizing of an entire folder
Long edge	Sets the longest dimension to a fixed pixel value and scales the short edge proportionally.	Mixed-orientation galleries where you want a consistent maximum size
Original (no resize)	Keeps original dimensions. Format conversion, color filter, rotate/flip, and watermark still apply.	Watermark-only runs or format-conversion-only passes

Why convert images to WebP?

WebP consistently delivers 25-35% smaller file sizes than JPEG or PNG at the same visual quality. Smaller images mean faster page loads, lower bandwidth costs, and better Core Web Vitals scores, specifically Largest Contentful Paint (LCP), which Google uses as a ranking signal. All modern browsers including Chrome, Firefox, Safari, and Edge support WebP natively.

WebP also supports transparency (like PNG) and animation (like GIF), making it a versatile single format for most web use cases. When you need lossless pixel-perfect output or compatibility with older software, PNG remains the right choice. For photographic content with no transparency requirement where WebP is not accepted, JPEG is the fallback.

Who uses a bulk image resizer and why

E-commerce teams use it to normalize product photos to consistent thumbnail sizes, convert camera JPEGs to WebP for faster product pages, and add watermarks to catalog images before publishing. Preset crop mode ensures every card image is exactly the same pixel size.
Social media managers use platform presets to prepare one batch of images for multiple channels at once — Instagram square, landscape, and story crops from the same original — saving hours of manual resizing in separate tools.
Web developers and designers use it to optimize image assets before committing to a repository or CDN, convert PNGs to WebP to improve Lighthouse scores, and generate srcset-ready variants at multiple sizes using the Scale by % mode.
Photographers and content creators use it to export client-ready watermarked galleries from raw high-resolution originals, applying a consistent logo watermark and Fit resize in one batch.
Marketing teams use the Open Graph 1200x630 preset and the Long edge mode to prepare images for blog posts, email campaigns, and press kits that require specific dimensions and consistent branding.

Private by design — no uploads, no tracking

This tool runs entirely in your browser using the HTML Canvas API. No image data is sent to a server at any point. Your photos never leave your device. There is no account, no login, no usage tracking, and no file size metering. Processing happens locally on your CPU, which also means it works offline after the page has loaded. It is safe for confidential product images, client work under NDA, and personal photos that should not be stored on third-party servers.

As a side effect of using Canvas for export, EXIF metadata including GPS location, camera model, and timestamps is stripped from the output. This is often desirable when publishing images publicly.

Frequently asked questions

How do I resize multiple images at once for free?

Upload all your images at once by dragging and dropping them onto the upload area or clicking to browse. Set your target dimensions, choose a resize mode (Fit, Crop, Fill, Percent, or Long edge), then click Process All & Download ZIP. The entire batch is processed locally in your browser at no cost, with no account or software needed.

How do I convert images to WebP format in bulk?

Upload your JPG or PNG images, set the output format dropdown to WebP, adjust the quality slider (75-85% is a good starting point for web images), and click Process All & Download ZIP. All images convert to WebP and download together in a single ZIP file. The savings badge on each card shows exactly how much smaller each file became.

Can I add a watermark to multiple images at once?

Yes. In the options panel, choose Text watermark to add copyright or brand text, or Logo / image to upload your PNG or SVG logo. Set the position, opacity, and size, then process the batch. Every image gets the watermark applied at the correct scale before it is downloaded.

What is the difference between Fit, Fill, and Crop resize modes?

Fit scales the image to fit inside your target dimensions while keeping its original aspect ratio. No padding, no cropping. Fill pads the image to match your target exactly using a background color you choose. Crop (cover) scales and center-crops the image so it fills the exact target dimensions with no padding or empty space, which is ideal for thumbnails and social posts that must be a specific pixel size.

Does this tool upload my photos to a server?

No. Everything runs locally inside your browser using the HTML Canvas API. Your images are never sent to a server, stored, or logged anywhere outside your device. This makes the tool safe for confidential product photos, personal images, and anything you want to keep private.

What is the best format for website images — WebP, JPEG, or PNG?

WebP is usually the best choice. It produces files 25-35% smaller than JPEG at the same visual quality, supports transparency like PNG, and is supported by all modern browsers. Use JPEG for photographs when WebP is not required. Use PNG only when you need lossless pixel-perfect output or very broad software compatibility.

How do I resize images for Instagram, YouTube, or other social media?

Click any of the social media preset buttons: Instagram Post 1080x1080, Instagram Portrait 1080x1350, Instagram Story 1080x1920, YouTube Thumbnail 1280x720, X / Twitter Header 1500x500, Facebook Cover 820x312, LinkedIn Post 1200x1200, Pinterest Pin 1000x1500, or Open Graph 1200x630. The preset automatically sets the exact dimensions and selects Crop mode so your images fill the frame without letterboxing.

Can I convert PNG to JPEG in bulk?

Yes. Upload your PNG files, set the output format to JPEG, adjust the quality slider, and click Process All. Note that JPEG does not support transparency. Any transparent areas in your PNGs will be filled with the background color from the Fill mode setting (white by default). If your PNGs have important transparency, use WebP to preserve it.

How do I compress images to reduce file size?

Select WebP as the output format and set quality to around 80%. WebP gives significantly smaller files than JPEG or PNG at equivalent visual quality. For photos, quality settings between 75 and 85% are a good balance. Check the file size savings badge on each processed card to see the exact percentage reduction.

Can I convert images to black and white or add a sepia tone?

Yes. In the Color filter section, click Grayscale (B&W) to remove all color from the batch, or Sepia (vintage) for a warm brown tone. The filter is applied after resizing and before watermarking, so it works correctly with every resize mode and output format.

Can I rotate or flip multiple images in bulk?

Yes. In the Rotate & Flip section, choose a rotation angle (0, 90, 180, or 270 degrees clockwise) and check the flip checkboxes for horizontal or vertical mirroring. These transforms apply to every image in the batch before the watermark is added.

Is there a file size or image count limit?

There is no hard limit set by the tool. Processing depends on your device's available memory and the browser's canvas limits. Very large images (above 8000x8000 pixels) or very large batches of 50 or more high-resolution images may be slow. Process in smaller groups if you run into issues.

What does the Long edge resize mode do?

Long edge resizes each image so its longest dimension (width or height) matches the pixel value you set, while keeping the original aspect ratio. This is useful for galleries with mixed-orientation images (landscape and portrait) where you want everything normalized to the same maximum size without cropping.

Will EXIF metadata and GPS location data be preserved?

No. The tool processes images through the HTML Canvas API, which exports pixel data only. EXIF metadata, GPS location, color profiles, and other embedded information are stripped from the output. This is actually a privacy benefit when sharing images publicly, as it removes device and location information automatically.

How does the file name template work?

The template uses tokens replaced automatically for each image: {name} (original filename without extension), {w} and {h} (output width/height in px), {ext} (format extension), and {i} (sequence number). For example, {name}-{w}x{h}-{i}.{ext} produces photo-1200x800-1.webp. This makes it easy to create structured, sortable filenames for e-commerce catalogs, content libraries, and asset pipelines.