How to Convert PNG to WebP
PNG files are the quiet bandwidth killers of the web. A single 4K screenshot can weigh 8 MB, and a site logo saved at the wrong size adds hundreds of kilobytes to every page view. WebP keeps PNG's best trick — full alpha transparency — while cutting typical file sizes by 26% or more. Here's how to convert cleanly with Re-Sizefy, entirely in your browser.
Step-by-step conversion
- Drop in your PNGs. Drag screenshots, logos, icons, or diagrams into the tool. Batch mode handles mixed collections at once.
- Select WebP output. Transparency is preserved automatically — the alpha channel survives the conversion, so rounded logos and cut-out graphics keep their see-through backgrounds.
- Choose lossy or lossless. For screenshots and most graphics, lossy WebP at quality 80–90 gives dramatically smaller files with no visible change. For a master logo you'll reuse for years, lossless WebP keeps every pixel identical while still beating PNG's size.
- Resize oversized graphics. A screenshot captured at 3840px wide but displayed at 800px is pure waste. Downscale to the actual display width during conversion — Re-Sizefy's multi-step downsampling (bicubic/bilinear) keeps text edges sharp.
- Download the batch. Multiple files export as a single ZIP. Use renaming rules (e.g., append
-web) so converted files don't overwrite your source PNGs.
Lossy vs lossless: which to pick
Lossy WebP throws away data the eye barely notices; it's ideal for screenshots, product renders, and photos with transparency. Lossless WebP compresses without discarding anything; choose it for logos, line art, and any graphic where a single altered pixel matters (think brand colors). A quick rule: if the graphic will be edited again later, go lossless and keep the PNG too; if it's final delivery for a website, lossy at high quality is the pragmatic choice.
Tips for crisp results
- Check text at 100%. Tiny UI text in screenshots is where artifacts show first. Compare the WebP against the PNG side by side before committing to a low quality setting.
- Mind the edges. Semi-transparent pixels around logos (soft shadows, anti-aliased edges) can fringe at very low quality. Stay at 80+ for anything with transparency.
- Strip oversized dimensions first. Converting a 4K PNG to WebP without resizing still leaves you with a huge file. Dimensions are the biggest lever; format is the second.
When to keep the PNG
Not everything should move. Keep PNG as your editable master — design tools and printers expect it, and re-exporting from a lossy WebP degrades quality. Also keep PNG for Open Graph and social preview images, where platform support for WebP is still inconsistent. The pattern that works: archive the PNG, ship the WebP.
Try it now
Open the free Re-Sizefy converter — drop your PNGs, pick WebP, download the ZIP. No sign-up, nothing uploaded.