Questions about photo resolution come up frequently, so I hope this helps everyone!
RESOLUTION OF PHOTOS FOR COMMERCIAL PRINTING
< 500KB only suitable for web500KB - 1MB suitable up to 1/8 page size
1MB-1.5MB suitable up to 1/4 page size
1.5MB - 2MB suitable up to 1/2 page size
3.5MB suitable full page size
> 3.5 MB very large files are sharper and crisper and very welcome
Never use software to force the resolution of the file larger. This does not improve quality.
CAMERA SETTINGS
Minimum requirements: A mid-range consumer camera or better. (Compact point-and-shot cameras and smart phone cameras can only produce small images for commercial printing)
Resolution: Set camera on highest possible quality setting
File type: If the camera supports RAW format, this setting will create the best quality photos. RAW format can only be viewed in professional software so it is best to set Camera on RAW + JPEG. This will produce two images, a high quality RAW photo and a jpeg for proofing.
JPEG: If camera only supports JPEG format, this is acceptable as long as highest possible settings are chosen.
Shout out to my friend Tammi for sharing this with me!