I'm not sure what the size requirements are, if we're looking at needing to get the dimensions down to a certain width/height, or if the file size needs to be smaller, but either way, there are a few ways you could meet those requirements. One way is if you or a friend has skill with Photoshop, and access to the program, you can size it down that way. Alternatively (and this might be easier), I do know there are online tools that allow you to resize without those higher level skills or programs, including, for example, this one:
https://www.adobe.com/express/feature/image/resize. I've never used those online tools, myself, since I do have Photoshop and know how to use it, but it might be just what you need.
