How to resize many photos or compress many PDFs at once

To resize a whole set of photos to the same KB limit, open Resize photo in KB, select Choose photos, pick up to 25 photos, set the limit and select Resize photo →. For PDFs, do the same in Compress PDF with Choose PDF files. Each file gets its own result line, and Download all as ZIP ↓ saves everything in one file. The files are processed on your phone or computer and aren’t uploaded to us.

This helps when a portal wants several documents under the same limit: four certificates under 200 KB each, or a photo, a signature and two ID scans under 100 KB. Doing them one by one is slow and easy to get wrong.

What you can do in one go

These tools accept more than one file and handle each file on its own:

Resize photo in KB and its presets, such as Resize photo to 50 KB. JPG, PNG, WebP and iPhone HEIC photos, each saved as a JPG.
Compress PDF and the fixed-size pages, such as Compress PDF to 200 KB.
PDF to JPG: the ZIP has one folder of page images for each PDF with more than one page.
PDF to Word: one Word file for each PDF.
Images to PDF with One PDF per image ticked, if each photo has to be its own PDF.
Remove hidden data, Protect PDF, Unlock PDF, Rotate PDF, Watermark PDF and Add page numbers.

The limits are the same everywhere: up to 25 files at once, 30 MB per file and 100 MB in total. If you need to join files into one PDF instead, use Merge PDF. That is a different job.

Resize several photos to the same KB limit

Open Resize photo in KB.
Select Choose photos. On a phone, tap each photo you want in the picker, then confirm. On a computer, hold Ctrl (Cmd on a Mac) to pick several, or drag them onto the box.
Type the limit in Maximum size in KB, or pick a Preset. Add a width or height only if the form asks for exact pixels.
Select Resize photo →. The list shows Working…, then Done with a small preview for each photo.
Select Download next to one photo, or Download all as ZIP ↓ for the full set.

The settings apply to every photo in the list, and the tool finds the highest JPEG quality that fits for each one separately. In our test on November 4, 2026, we chose three real phone photos: a 5712 × 4284 iPhone 15 Pro HEIC, a Samsung HEIC taken upright and a Nokia HEIF. With a 100 KB limit in Chrome on Android, they came out at 90.1 KB, 89.1 KB and 95.7 KB. The iPhone photo became 1048 × 786 pixels at 62% quality. Safari on iPhone gave slightly different numbers, 83.0 KB to 92.9 KB, because each browser’s JPEG encoder works a little differently. All of them were under the limit.

A mixed set of six photos at the 50 KB preset (two HEIC, one HEIF, a JPG, a PNG and a WebP) went from 20.6 KB to 48.6 KB each. The ZIP names each file after the original plus its new size in pixels, for example iphone15pro-670x503.jpg, so you can tell them apart in the upload form.

Compress several PDFs at once

Open Compress PDF.
Select Choose PDF files and pick your PDFs.
Choose a Compression mode. Optimize — keep page content leaves text and links as they are. Image-based — for scans and photos makes scans and phone photos saved as PDF much smaller. Pick Target size — for upload limits when the portal gives a limit.
Select Compress PDF →, then Download all as ZIP ↓.

In our test, three single-page PDFs made from those phone photos weighed 1.28 MB to 1.89 MB each. In Image-based mode they came out at 64.0 KB, 120.0 KB and 124.9 KB, 93% to 95% smaller, with almost the same results in Chrome and Safari. Each line also warns that an image-based copy loses searchable text, links and forms. That doesn’t matter for a photo of a certificate, but it does for a typed document you want to keep searchable, so read why a PDF won’t get smaller before you pick that mode for one.

Reading the results

Each row shows the file name, its state and one line about the result. The line under the list totals it up, such as “3 of 3 files done”. You can download a single file from its row without taking the ZIP.

If one file can’t be processed, its row says Not processed with the reason, and the other files still finish. For example, if a PDF needs a password to open, unlock it first with Unlock PDF, if you are allowed to, and run it again on its own.

Cancel stops the batch. Files that were already done stay in the list and in the ZIP, and the file in progress and the rest show Not started. Your original files are never changed. You always get new copies.

If it doesn’t work

“Select no more than 25 files at once.” Split the set into two batches.
“The combined input must be 100 MB or smaller.” Phone videos or very large scans add up quickly. Run a smaller batch.
The first HEIC photo takes a few seconds. Browsers that can’t open HEIC on their own download a decoder of about 3 MB from this site the first time. The browser keeps it, so later photos are quicker and it works offline after that.
Nothing happens when you tap Download on an iPhone. Tap and hold the button, or use Share, then Save to Files.
A photo is still too big for the form. Check whether the form also fixes the pixel size. Fewer pixels give the tool more room to keep quality under a low limit.

Upload forms usually want the files themselves, not the ZIP. Open it in Files on iPhone, your phone’s file manager on Android, or by double-clicking on a computer, then upload the files one by one.