OrbConvert converts your image files online. Amongst many others, we support PNG, JPG, JPEG, WEBP, GIF, SVG and TIFF. You can use the options to control image resolution, quality and file size.
From
Flexible Image Transport System
The standard format of astronomy, carrying scientific data alongside the image. Files are typically far larger than the same picture as PNG.
All FITS conversionsTo
JPEG 2000
A wavelet-based successor to JPEG that holds quality better at small sizes and can carry transparency. It never replaced JPEG on the web, so browser and desktop support is patchy.
All JP2 conversions