JPG, PNG or WEBP: which image format should you use?
JPG: efficient compression for photographs
JPG uses lossy compression, which discards image detail that is difficult for the human eye to notice. This makes it extremely efficient for photographs and other natural images with smooth color transitions.
The trade-off is permanence: every time a JPG is re-saved, a little more detail is lost. JPG also has no support for transparency, so any transparent area is filled with a solid background color, usually white.
PNG: transparency and sharp edges
PNG uses lossless compression, so the image is reconstructed pixel for pixel. It supports a full alpha channel, which makes it the natural choice for logos, icons, screenshots, and interface graphics that need transparent backgrounds.
The downside is size. A photograph saved as PNG can be several times larger than the same photo saved as JPG, with no visible benefit. For sharp-edged graphics the situation reverses: text and flat colors stay perfectly crisp in PNG, while JPG adds visible artifacts around edges.
WEBP: the modern balance
WEBP supports both lossy and lossless compression, transparency, and animation, and it typically produces files that are 25 to 35 percent smaller than JPG at comparable quality. All modern browsers now display it without plug-ins.
When in doubt, WEBP is a strong default for web use. The remaining caveats are compatibility with older software: some desktop applications and legacy systems still do not accept it.
Simple rules for choosing
Use JPG for photographs that do not need transparency. Use PNG for graphics with sharp edges, text, or transparent backgrounds. Use WEBP when file size matters and the target platform supports it.
If a file must open in older software without question, stay with JPG or PNG. If it is destined for the web and modern viewers, WEBP delivers the best balance between quality and transfer size.