Currently the maximum size of images that can be used within a report are limited to 1500 kb due to hard coded limit within RDL expression (https://learn.microsoft.com/en-us/power-apps/maker/model-driven-apps/rdl-sandboxing). Since reporting will be always a thing within dynamics and especially for sales reasons there must be a possibity to use at least images that are greater than 1500kb.

My suggestion would be 5000 kb but 3000 kb as a minimum.