Most images are already produced in a compressed format and zipping them will not usually create a file size much smaller.
Your best bet, if you have the images already and they are of reasonably good quality for viewing then you can upload them to your OneDrive or Google Drive and share a link to them.
Otherwise you might try reducing the quality DPI on whatever device you are using to capture the images to produce a file size smaller than 1 meg.
It's a balance between getting an image of sufficient quality combined with a size (dimension) that is suitable for us to see what you are seeing.