Changing resolution for outgoing pictures

[Android Central Question]

I am having trouble transmitting pictures through a proprietary app my employer uses. It has been suggested that decreasing the resolution on my photos might solve the problem. I seem to remember having played with resolution choices on my Android MotoX Pure Edition (2015) but now am unable to find the settings where I was doing it. Can you help me lower the resolution settings on the pictures? Camera resolution settings might also be the problem, I am not sure. I can only test the effectiveness of any fix by attempting to complete a work project with the app so testing my fixes are problematic. This is preventing me from getting work done. Can you help?