I tried to make a custom pack containing an object texture which was very large (e.g. 800x800px) and the object would never show up in the library. Once I scaled the image down to 128x128px, repackaged and reloaded the pack, the object then showed correctly in the Library and was useable on the map. There should at least be a warning about an image being too larger or ideally the app would automatically scale down the imported image to maximum allowed size.
I tried to make a custom pack containing an object texture which was very large (e.g. 800x800px) and the object would never show up in the library. Once I scaled the image down to 128x128px, repackaged and reloaded the pack, the object then showed correctly in the Library and was useable on the map. There should at least be a warning about an image being too larger or ideally the app would automatically scale down the imported image to maximum allowed size.