Yes, you can. From your zInspector account, click on Properties (https://portfolio.zinspector.com/property/list/), click on the appropriate Property Name, and then click on Upload Photo. You can upload photos up to 8 MB in size.  

This is a great feature if you have legacy photos, or take new photos with a DSLR camera. You can bulk upload many pictures at once .

In the demonstration video, only one photo is shown to be uploaded at a time, although you can bulk upload many photos at once in the current version. The maximum number of photos is limited by the memory of your computer. Typically, 10-20 photos per upload works easily.

You can use this method to upload photos to any past inspection. Simply pick the same Property, Date, and Activity type.