Image Uploading Criteria
Save images in .jpg, .gif, or .png format only.
.pdf, .psd, .tff, and .doc files are NOT web-compatible.
Only use letters, numbers, underscores, and hyphens in file names. Other characters (like question marks, percent signs, and ampersands) may upload incorrectly or cause unexpected behavior in galleries.
When it comes to image size, bigger isn't always better. There is a 20 MB limit on all images, but we recommend you use image files of less than 500 KB for best results.
Save images in RGB color mode. Print mode (CMYK) won't render in most browsers.
Save images in the sRGB color profile. If images don't look right on mobile devices, it's probably because they don't have an sRGB color profile.