I have asked this question before. Every time I try to post a picture I get a message saying it's to big to post. I have posted here in the past, so I don't know what has changed. How can I make the picture smaller or how do I post it?
A simple conversion to smaller file size is to save as a .gif rather than .bmp, .jpg, or other file format. A .gif only has 256 colors making it a smaller file. I think file size upload limit is 1 megabyte. Try an image editor? Here's a free one; https://www.gimp.org/
You'll need to resize the picture, I use a photo editing app on my cellphone. You can find a number of them for a home pc, laptop or cellphone in your App Store.