Shrink PNG Diagrams for Slide Decks Without Losing Readable Text (PNG to WebP)

Slide decks fail in a quiet way: the diagrams look fine on your laptop, then turn into blurry blocks on the projector — or the file gets so heavy that sharing it becomes a chore. The usual culprit is PNG diagrams saved at full screenshot resolution. PNG is lossless, which is great for sharp text, but it is also heavy, and a deck full of diagrams adds up fast.

The fix is not to shrink the diagram until the text is unreadable. It is to change the format. WebP keeps text sharp at much smaller file sizes than PNG, and every modern browser and most presentation tools handle it well. The workflow I use:

1. Keep the original PNG. Never overwrite your source diagram — you may need it at full resolution later.
2. Convert a copy to WebP. Aim for a copy you can actually read at presentation size, not the smallest file possible.
3. Check the text at 100% zoom. If small labels blur, that copy is too aggressive — reconvert with a gentler setting or keep that one diagram as PNG.
4. Replace only the heavy diagrams. Charts, screenshots of dashboards, and annotated mockups benefit most; tiny icons can stay as they are.

One caution: if your deck must be opened in an older tool that does not support WebP, convert a copy back to JPG or PNG for that audience. The point is to shrink the working copy, not to lock yourself into one format.

You can convert PNG diagrams to WebP for slides: drop in the PNGs, download WebPs, nothing is uploaded and no account is needed. That matters for decks that contain unreleased product screenshots or internal numbers — the files never leave your device.

Disclosure: I'm the developer of FileOnTap. The "keep the original, convert a copy, check the text" order is the real takeaway whichever tool you use.