Published 2026-09-29
Attaching a photo to a message or email often runs into a size limit. Compressing it blindly can visibly hurt quality, but most of what inflates file size has little to do with quality at all.
Three things that inflate file size
| Factor | Effect on size |
|---|
| Resolution (width × height in pixels) | The biggest factor by far — halving both dimensions cuts size to roughly a quarter |
| File format | The same photo can be several times larger as PNG than as JPG (see the format comparison guide) |
| Metadata | Location and device info, plus small preview thumbnails some editing software embeds — usually tens to hundreds of KB |
Start with what barely affects quality
- If the photo is far bigger than it needs to be, scale it down. Most social platforms display around 1080px wide, but people often upload originals well over 4000px. Since it gets scaled down on screen anyway, the difference is hard to notice.
- If a photo doesn't need transparency but is saved as PNG, switch it to JPG. At a reasonable quality the loss is barely visible, while the file shrinks considerably.
- Strip the metadata. Beyond location and device info, some software embeds a small preview thumbnail inside the file. This can be removed without touching a single pixel.
These three steps alone usually cut a photo to under a quarter of its original size. If that's still not enough, consider lowering the compression quality next.
Doing it in prezll
- Upload the photo. The original size is shown at the top of the screen.
- Use Resize to scale to the size you'll actually use — 1080px wide is common for social media. The estimated size updates as you change it, so you can see the effect immediately.
- If it's a PNG that doesn't need transparency, keep in mind prezll exports in whichever format you uploaded, so converting beforehand (or uploading a JPG version) keeps the smaller format.
- If the photo doesn't need editing at all, use "Remove metadata only" while no tool has been applied yet, to get the original at full quality with just the location and device info stripped.
- Check the estimated size shown before downloading to confirm you've hit your target.
Shrink a photo now