An image format is a tradeoff. A photograph, a transparent logo, and a screenshot do not need the same treatment. Start with the image’s purpose, then choose the format and dimensions together.
Use JPG for photographs
JPEG works well with photographs and other images containing gradual changes in color. It uses lossy compression: the encoder discards some visual information to save space. At sensible quality levels, that loss can be hard to see at the size where the image will be displayed.
JPEG does not preserve transparency. When ERITHRA converts a transparent PNG to JPEG, it places the image on a white background. Check the result before publishing a logo or graphic that was designed for a dark surface.
Avoid repeatedly editing and resaving a JPEG. Keep the original, make your changes once, and export a fresh copy for each intended use.
Use PNG for crisp graphics and transparency
PNG uses lossless compression and supports alpha transparency. It is useful for interface screenshots, diagrams, and graphics with sharp edges. A PNG containing a full-resolution photograph can be much larger than a visually similar JPEG or WebP.
Converting a JPEG to PNG does not restore details that were already lost. It changes the container and prevents additional JPEG compression at that conversion step. If your aim is a smaller file, PNG is rarely the best choice for a photograph.
Consider WebP for web delivery
WebP supports both lossy and lossless encoding, as well as transparency. It can provide useful size savings for web images, but the actual result depends on the source and quality setting. Compare real outputs instead of assuming one format is always smaller.
ERITHRA’s JPG to WebP converter exports a still WebP image through the browser. Animated sources are outside this tool’s scope. For browser compatibility details, consult MDN’s image format guide.
Resize before compressing
A 6000-pixel-wide photo used in a 1200-pixel content area contains far more pixels than that display needs. Use the image resizer first, allowing for the intended display density. Then use the image compressor and inspect fine details, edges, and text at a realistic size.
Compression is not guaranteed to reduce every file. A source may already be efficiently encoded, and exporting it again can make it larger. Keep the smaller acceptable result and retain your original separately.
A quick export checklist
- Choose dimensions for the actual placement.
- Decide whether transparency is essential.
- Compare output size and visual quality.
- Confirm that the receiving app supports the format.
- Keep the original file for future edits.
Color profiles, metadata, and animation may change or disappear during a canvas-based export. For photography or archival work where these details matter, use a dedicated image editor with explicit profile and metadata controls.