iStock accepts RGB JPG files only. TIFs, PNGs and PSDs will be declined. CMYK images will also be declined.
iStock accepts files 1600 x 1200 pixels or larger. Any file smaller than 1600 x 1200 pixels will be declined. iStock offers different sizes of each image on the site and our file pricing is based in part on the image dimensions, so it's often in your best interest to provide an image in the largest pixel dimensions possible. iStock will automatically create all the different smaller size files from the full resolution file that you upload.
iStock will not accept files that have been up-sampled or "rezzed-up". In other words, you can't increase the pixel dimensions to be larger than the file's native size.
4.0 Quality Standards
6.0 Title, Description & Keywords
8.0 Model & Property Releases