I do not believe the file size would be an issue. That the file size will slow the loading of the images I agree? but I have my doubt they would not Drag & Drop.
I just snapped off a few pics of an engine .? Both end up as? 1.16mb files, 3072 X 2048, 72 dpi, 24 bit depth? JPG.??? Drag&Drop directly from the? mem card into Labels & Media.
Had no issue defining them as? Main and ICON of a roster entry.?? Only difference I see is a few micro seconds more to load? when I click on the roster entry for the image to show in window.
compared to the GIF @ 20kb. These show up instantly.
Win10. JAVA 1.8.0_231, JMRI 4.18,?
Must be something in permissions for the USER ID used.
Marc