Bulk Image Resizer – Batch Resize Multiple Photos at Once
Free bulk image resizer: select multiple high-resolution phone photos and batch resize them to one common size, such as 1920px on the long edge, then download everything as a ZIP. Keeps aspect ratio for portrait and landscape shots, supports HEIC, and never uploads your images.
Choosing a long-edge size
The example dimensions and pixel ratios assume a 4032×3024 photo (about 12 megapixels), a resolution many smartphones use.
| Long edge | Resized dimensions (example) | Share of original pixels | Good for |
|---|---|---|---|
| 3,840 px | 3,840 × 2,880 | 91% | Full-screen viewing on 4K displays, or archiving while keeping plenty of detail. |
| 2,560 px | 2,560 × 1,920 | 40% | High-resolution screens and prints up to about 5×7 inches (roughly 2,100px on the long edge at 300 dpi). |
| 1,920 px | 1,920 × 1,440 | 23% | Fills a Full HD screen. If you are unsure, this is the recommended size for websites, social media and sharing. |
| 1,600 px | 1,600 × 1,200 | 16% | Blog posts and email attachments. Also enough for a 3.5×5 inch print (about 1,500px on the long edge at 300 dpi). |
| 1,280 px | 1,280 × 960 | 10% | Plenty for sharing in chat apps or pasting into documents and slides. |
| 1,024 px | 1,024 × 768 | 6% | Handy when an upload form has a strict file size limit. |
| 800 px | 800 × 600 | 4% | Thumbnails for galleries and small product images. |
What is a bulk image resizer?
A bulk image resizer shrinks many images at once using a single rule. Photos taken with a modern smartphone are 12 megapixels or more, so sending them as they are can exceed email attachment limits or make a web page slow to load. Opening each photo in an editor to change its size one by one takes a long time, so this tool lets you resize a whole set of vacation or event photos simply by selecting them.
You choose just one rule, such as "make the long edge 1920px" or "shrink everything to 50%". With the long-edge setting, portrait photos are scaled by their height and landscape photos by their width, so a mixed set ends up feeling the same size. The aspect ratio is always preserved, and images that are already smaller than your setting are never enlarged. The tool can read iPhone HEIC photos too, and because all processing happens in your browser, your images are never sent to a server.
How to batch resize images
- Choose how to resize Pick Long edge, Width, Height or Percentage. For phone photos that mix portrait and landscape shots, Long edge works best.
- Enter a size Type a number or tap one of the common sizes. If you are unsure, 1920px on the long edge works well for almost any website or sharing purpose.
- Pick the format and quality Keeping the original format is usually fine; HEIC photos are converted to JPEG. Choose WebP if you want even smaller files.
- Select your images Drag and drop files onto the box, or click it to choose several at once. Resizing starts right away and a progress bar shows how far it has gone.
- Save as a ZIP Click "Download all as ZIP" to save every resized image in a single ZIP file. You can also save images one at a time.
Tips for getting more out of it
- Resized images are saved as new files. Your original photos are never modified, so you can always go back to the full-size versions later.
- After changing a setting, click "Redo with these settings" to resize the same images again without selecting them a second time. This makes it easy to compare results and find the right size.
- Resizing a 12-megapixel photo to 1920px on the long edge leaves about a quarter of the pixels. The exact file size depends on the photo, but it usually shrinks to a fraction of the original.
- If the files are still too large for an upload limit after resizing, run them through the image compressor to lower the quality and make them lighter still.
- If you need a different size or crop for each image, the image resizer or the image cropper is a better fit.
When to use a bulk image resizer
Sharing trip or event photos
Sending dozens of full-size photos quickly runs into email attachment limits or chat upload caps. Resizing them to around 1600–1920px and bundling them in a ZIP makes them much easier to send in one go.
Publishing images on a blog or online store
An image larger than its display area does not look any sharper on a web page; it only loads more slowly. Shrinking images in bulk before uploading them helps your pages load faster.
Meeting upload limits on application forms
When a form only accepts files up to 2MB each, reducing the dimensions usually gets photos under the limit without a visible loss in quality. You can handle every required image in a single batch.
Removing location data before posting
Resized images do not keep EXIF data, so you can post photos without revealing where they were taken, such as your home. Resizing and cleaning happen in a single step.
Inserting photos into documents
Pasting full-resolution photos can make a document balloon to tens of megabytes. Shrinking them to about 1280px on the long edge first keeps the file easy to share.
Bulk image resizing terms
- Long edge
- The longer of an image's two sides, width or height. Setting the long edge lets you resize portrait and landscape images to the same overall size regardless of orientation.
- Pixel count
- The total number of dots (pixels) that make up an image, calculated as width × height. A 4032×3024 photo has about 12 million pixels. Halving both dimensions leaves a quarter of the pixels.
- Aspect ratio
- The ratio between an image's width and height. This tool always preserves it, so your photos are never stretched or squashed.
- Resampling
- The process of calculating new pixel colors from the original pixels when an image changes size. When shrinking, nearby pixels are averaged, and the method used affects how smooth the result looks.
- EXIF
- Shooting information embedded in digital photos, such as the date and time, camera model, GPS location and the orientation of the picture.
- HEIC
- The default photo format on iPhones. It keeps similar quality to JPEG at a smaller file size, but Windows and many browsers cannot open it without extra support.
Frequently asked questions
Side Note — Why shrunken photos turn jagged
Making an image smaller sounds easier than making it larger. You are only throwing information away, so there is nothing to invent. In practice, though, shrinking is where things often go wrong. When a 4000px photo becomes 800px wide, each new pixel has to stand in for a 5×5 block of 25 original pixels. If the software simply picks one of those 25 pixels instead of averaging them, thin power lines and the edges of text break up into stair-step patterns known as jaggies.
An even stranger problem is moiré. When a regular pattern, such as the fine stripes on a shirt or rows of office windows, is thinned out carelessly, wavy bands appear that were never in the original photo. It is the same principle as aliasing in digital audio, where a tone that is too high gets recorded as a false lower tone, and it is explained by the sampling theorem: detail finer than the sampling grid cannot be captured correctly and turns into a fake pattern.
The basic cure is to blur away detail that is too fine before thinning the image out. Resampling methods such as bicubic and Lanczos do both at once by taking a weighted average of the surrounding pixels. This tool shrinks images in stages, halving the size at each step instead of jumping straight to the target. Because nearby pixels are averaged at every step, the result tends to come out smooth even when relying on the browser's built-in scaling.
The idea of shrinking by halves has a long history in 3D graphics, too. Mipmapping, introduced by Lance Williams in 1983, stores each texture in advance at 1/2, 1/4, 1/8 of its size and so on, so that distant surfaces are drawn from a pre-shrunk copy. It prevents far-away floor patterns from shimmering or turning into moiré. In other words, an entirely different field ran into the same problem as photo resizing and solved it in the same way.