Image Format Converter
Convert images between PNG, JPEG, and WebP formats
Frequently Asked Questions
What does the image format converter do?
It converts between PNG, JPEG, and WebP in the browser using the Canvas API to decode and re-encode, with adjustable quality. Use it to shrink files, meet platform requirements (e.g., WeChat only accepts JPG), or produce optimized WebP variants for the web.
Which format should I pick?
- **PNG**: lossless, supports transparency — great for UI screenshots and icons - **JPEG**: lossy, small, best for photos, no transparency - **WebP**: modern format with PNG-style transparency and JPEG-beating compression For a fast web hero image, WebP wins. For older devices or print, stick with PNG/JPEG.
Can I convert multiple images at once?
Yes — drag in several files and download them one by one or as a zip. For very large batches (dozens+), split into smaller batches to keep browser memory healthy.
Why does file size grow or shrink after conversion?
PNG → JPEG usually shrinks but loses transparency. JPEG → PNG often grows because PNG encodes the already-lossy pixels losslessly. WebP typically beats both. The quality slider controls lossy compression — 100% is largest/sharpest, lower values compress harder.
Are my images uploaded?
No. FileReader + Canvas read and export images locally — nothing goes to a server — which is ideal for personal photos or brand assets.
How does this compare to Photoshop or online compressors?
Photoshop is powerful but heavy. Online compressors like TinyPNG often produce smaller files via server-side algorithms but require upload. DevToolkit strikes a balance between privacy and speed — no upload, no queue, perfect for everyday conversions.