The recommended image sizes are:
- Mobile mockup -> 560 x 1212px (Retina -> 1120 x 2424px)
- Tablet mockup -> 732 x 1064px (Retina -> 1464 x 2128px)
- Desktop mockup -> 1150 x 972px (Retina -> 2300 x 1944px)
Important: you don't need to match these exact sizes. All device mockups in UXfolio use standard Apple ratios. So, the most important thing is that you export your images in a large size. After upload, they'll be fit into the canvas without distorting your image.