well, assuming you have a PC, apologies if you don't, I would use MS PAINT;
Open the picture file
pick the rectangular "select" icon button
highlight the section of picture you want
when you let go of the mouse the cursor will change to a four-arrows-pointing-outward image.
Pressing the mouse button down again; drag your selection into the top left of the image window.
Click outside of the pic you want, and you will see the outermost corners of the image window get little squares (and the middle of each edge too.
Put your cursor over the one in the bottom right corner until a double-headed arrow appears; then drag the square up leftward until the junk is obscured, and what is left is the image you want.
Hope that is detailed enough without being insulting... regards... x2zero