You finally find the right form, fill in every field, and then it rejects your photo: file too large, maximum 100KB. A photo straight off a phone is usually 3 to 5 MB, so it needs to get about forty times smaller.
The good news is that it only takes a minute, and you do not need Photoshop or an app. You can do it in your browser with a free tool like Squishly Tools, which compresses your files on your own device, so they are never uploaded to anyone’s server. That matters when the file is an ID copy, a payslip or a proof of address.
The quick way: compress to an exact size
If a form tells you the limit, use a tool that aims for that size. It lowers the quality little by little until the file fits, so you keep as much detail as possible.
- Compress an image to 100KB For most job applications, university portals and online forms.
- Compress an image to 50KB For passport-style photos and stricter government and exam forms.
- Compress an image to 20KB For signatures and very small thumbnails.
- Compress an image to 200KB or choose your own size in KB, for anything else.
Step by step, in about a minute
- Check the limit. Look for the maximum file size and the formats accepted. Most forms want JPG, some also take PNG or PDF.
- Convert iPhone photos first. If your photo ends in .HEIC, convert HEIC to JPG before anything else. Many forms do not accept HEIC.
- Resize very large photos. A 4000 pixel wide photo is far bigger than any form needs. Resize it to about 1200 pixels wide and it will compress much more cleanly.
- Compress to your target. Pick the size you need, add the image and download the result. Check it is still clear before you upload it.
How small should my image be?
If nobody gives you a limit, these are sensible targets:
| What it is for | Aim for |
|---|---|
| Signature for a form | Under 20KB |
| Passport or profile photo for a form | Under 50KB |
| Documents and photos for applications | Under 100KB to 200KB |
| Photos on your website | Under 200KB to 300KB each |
| Big hero image on a website | Under 400KB |
| Email attachments | A few MB in total |
Compressing images for your website
This is where image size quietly costs businesses money. Heavy images are the most common reason we see websites load slowly on mobile data, and slow pages lose visitors and rank lower on Google.
- Resize to the size it is shown. A photo shown 1200 pixels wide does not need to be 6000 pixels wide.
- Use WebP. WebP files are usually much smaller than JPG and PNG at the same quality. Convert JPG to WebP or PNG to WebP before you upload.
- Compress in batches. Do a whole folder at once, then upload the smaller versions.
Not sure if images are what is slowing your site down? Our free website check tests your speed on mobile and tells you what to fix first.
What about PDFs and videos?
The same idea works for other files. You can compress a PDF that is too big to email, merge several PDFs into one when a form only allows a single upload, turn photos into a PDF with images to PDF, or compress a video so it fits on WhatsApp or email.
Try Squishly Tools, free.
Compress images to any size, convert to WebP, merge PDFs and shrink videos, right in your browser. No uploads, no sign up.
Open Squishly Tools