There are two aspects to file size - the level and type of compression, and the image size in pixels.
For here (YACF), no more than 1024 pixels wide is usually fine - unless the image has lots of detail necessary.
Your latest image is 3,024 x 4,032 pixels, so 9 times too big for what is needed. It is 2MB, and I reduced it to 340KB by reducing the pixel width to 1,024 - see below
If you don't have software to reduce the size of the images, have a look at how you are scanning them. Reduce the scanning resolution. Image sizes are a bit of a dark art - seemingly impenetrable, but easy once you know how and if you have the right software.