I know that many of us love to upload lots of pix to our posts, and if they are within the dpi limit for jpgs they will be inserted without a problem. For instructions on how to do that, check out a different post here in the Technical Section.
I'm writing about the size of the image once it's in this box. After you've uploaded a pix, and clicked Insert, it's often huge and unruley. So here's the simple way to make it visible, but not like a poster - more like a collage.
this is big.
Click the image when you insert it, and 4 little white squares appear at each corner of the photo.
Mouse to one corner, hold down left button and drag toward the center, diagonally of the pix to resize it. It will get smaller from any corner while retaining the proportion. If you use the buttons in the middel or top, it will change the porportions. This second pix I inserted, reduced the size, and dragged next to the first one. Use your arrow buttons to get your curser where you want it, and use the space bar to insert a few spaces between them, or hit enter to drop it down to the next line. Try it, it's fun!