Bulk Image Resizer

Image resizing without quality loss depends on direction.

Scaling down (reducing pixels) is always lossless relative to the new size — you are removing pixels, and the remaining pixels are unchanged. Scaling up (enlarging beyond the original) introduces interpolation: the algorithm has to invent new pixels from surrounding data, which can reduce sharpness. For best results when scaling up, use Lanczos or bicubic interpolation (which this tool uses by default), and avoid upscaling beyond 150% of the original — beyond that, the added pixels become visibly soft.

All processing is local. Unlike ImageResizer.com (which uploads to cloud servers, limits free use to 50 files, and stores images for 24 hours), this tool resizes entirely in your browser. No account, no upload, no storage of your images on any server. This matters especially for confidential content — product images before launch, personal photos, and work files that you would not want stored externally.

1. Upload Your Image(s)

Drag your files onto the upload area or click to browse. JPG, PNG, and WebP files are supported. For batch resizing, upload all images at once — there is no file count limit. Mixed-orientation batches (landscape and portrait photos together) are handled correctly; each image is resized independently.

2. Choose Your Resize Mode and Set Dimensions

Select from four resize modes: By Pixels (enter exact target width × height), By Percentage (enter scale factor, e.g., 50% to halve dimensions), By File Size (enter target KB/MB — the tool reduces dimensions and quality together to meet the size limit), or By Longest Side (enter one value and the other side scales proportionally). For aspect ratio handling: choose 'Maintain aspect ratio' to avoid distortion (the default), 'Pad with white' to add white borders to reach exact dimensions without cropping, or 'Crop to fill' to fill the exact dimensions by cropping the edges.

3. Resize and Download

Click Resize All. All images are processed simultaneously. For single files, download directly as JPG, PNG, or WebP. For batches, download as a ZIP archive with original filenames preserved. Processing speed depends on your device — a modern laptop resizes 100 photos in under 10 seconds.

Manually resizing photos one at a time is one of the most common time sinks in image-heavy workflows.

Batch processing — applying the same resize settings to hundreds of photos simultaneously — transforms what used to take hours into minutes. Here are the three most common professional workflows:

Photographers — client gallery delivery:

Photography clients often request web-ready galleries where each image is under a specific file size (typically 1-2MB) or at a specific pixel width (typically 2000px on the long side for print-quality web display). A 200-photo event shoot at 20-25MB per DSLR raw-exported JPEG needs to be batch-reduced before gallery delivery. Upload the entire shoot, select 'By Longest Side' and enter 2000px — every image (landscape or portrait) scales to 2000px on its longest side with aspect ratio preserved. If the client needs files under 2MB, follow with a batch compression step using the Compress to 2MB tool. The entire 200-photo gallery is processed in minutes.

E-commerce sellers — product catalogue standardisation:

Amazon, Etsy, Shopify, and WooCommerce all recommend square (1:1) product images at 1000×1000 pixels or larger. A product catalogue with 300 items shot at various compositions and orientations needs standardisation before bulk upload. Select 'By Pixels', enter 1000×1000, and choose 'Pad with white' for aspect ratio handling — this adds white borders to non-square originals rather than cropping, preserving the full product. The result is 300 consistently-dimensioned images ready for any marketplace upload. For listings where the platform enforces a maximum file size (some marketplaces cap product images at 500KB), follow with a batch compression to 500KB.

Web developers — responsive image preparation:

Modern responsive web design requires multiple image sizes: a full-width hero image at 1920px, a blog featured image at 1200px, and a mobile-optimised thumbnail at 600px. For a website with 50 blog posts, each needing all three sizes, that is 150 individual resize operations. Batch process the originals three times with different pixel targets, producing three complete sets. Web developers using Next.js, Gatsby, or WordPress's image optimisation pipeline can further automate this — but for content managers who need to prepare images before upload, batch resize produces all required sizes in a single session.

Performance guidance for large batches:

• Close other browser tabs before processing 200+ files — the tool uses your device's memory and CPU.
• For 500+ file batches, split into two sessions of 250 rather than one continuous batch, especially on devices with less than 8GB RAM.
• HEIC files from iPhone require a decoding step before resize — HEIC-heavy batches take 2-3× longer than equivalent JPG batches.
• Download starts immediately after processing — for 500+ files the ZIP creation itself takes 15-30 additional seconds.

The most common mistake when resizing images is choosing the wrong mode for the goal. Here is the decision framework:

Use By Pixels when:

• You are preparing images for a platform with specific pixel dimension requirements (Instagram 1080×1080, YouTube thumbnail 1280×720, Facebook cover 820×312).
Instagram presets (1080×1080, 1080×1350, 1080×1920) — use dedicated Instagram Image Resizer
Resize photo for Facebook profile or cover — use dedicated Facebook Image Resizer
Resize to YouTube thumbnail (1280×720) — use dedicated YouTube Thumbnail Resizer
• You are standardising a product catalogue to consistent dimensions (e.g., all 1000×1000 for e-commerce).
• The output file needs to be a precise size that matches an import specification (design software, CMS templates, print templates).

Use By Percentage when:

• You want to proportionally reduce a batch of photos without knowing or caring about the exact output pixel count (e.g., 'reduce everything by 50%').
• You are preparing photos for email or WhatsApp sharing — a 50% reduction typically takes a 4-8MB smartphone photo to 1-2MB, which transmits quickly.
• You want all original aspect ratios preserved without any padding or cropping — percentage scaling is always proportional.

Use By File Size when:

• You have a strict file size limit from a portal or system (DS-160: max 240KB, certain HR systems: max 200KB, YouTube thumbnail: max 2MB).
• You want the highest possible quality within a size constraint — the tool finds the optimal balance between pixel reduction and quality compression.
• You are not concerned about the exact output pixel dimensions, only that the file meets the upload size requirement.

Important distinction — resizing vs compressing:

Resizing (this tool) changes the pixel dimensions of the image. Compression changes the quality setting of the encoding without changing pixel dimensions. To reduce file size: resizing down reduces file size because there are fewer pixels to store. Compression reduces file size by allowing more quality loss in the encoding. For the best result at a specific file size target: resize down first (removes pixels), then compress (reduces encoding quality) — this two-step approach produces better quality at the same final file size than compression alone. Use the dedicated Compress to 100KB / 200KB / 500KB tools after resizing for specific file size targets.
After resizing, compress to under 100KB for visa portals and government forms