Convert x3f to png Online: x3f2png

You can use Tom's Editor to easily convert images from
Sigma Camera RAW Picture File .X3F to Portable Network Graphics .PNG.
Tom's Editor is a free, online image manipulation and converter program.

Go to Tom's Editor

X3F

Sigma Camera RAW Picture File is an image format with extension X3F.

PNG

Portable Network Graphics is an image format with extension PNG.