Help with pictures

I have recently started putting pictures on my computer and sending them in e-mails and to DG. Today I find that my pictures are all of a sudden big and blurry and the people to whom they are sent are getting just a large section of the picture like it is blown up. Don't know what I have inadvertantly hit and caused this. Someone help me please. Also the details of the pics say something like 1305 KB for the size and the dimensions say 4000x 3000 when the pic when highlighted say something like 1.27 MB. What is going on. I think this happened yesterday after I tried to send a file to GW and they refused it saying it is too large I just thought I had too many pictures I did try to send several at once. Hope I am making myself clear.
The very computer non savvy
Veronica