A minimum photo size of 640x480 pixel resolution is required to upload photos in the OMS.

Photos smaller than 640x480 resolution will not display in the photo uploader.

Why the minimum photo size?

In order to provide high-quality property listings to the public, we are enforcing minimum photo quality. The minimum size is also required by the OMS reporting system in order to display brochures and stock reports correctly.

Also see:

Help on uploading property photos