Wow....4000x2250 @ only 1.74mb.
Mine are 4288x2848 @ 3.5mb. Not to much bigger dimension wise. But a big difference in size. Shouldn't matter though.
I resize mine down to 640x480 with Picture Resize Genius, and upload to Photobucket, then post to where ever I do that stuff.
As said previously, copy the img code for use on forums. Paste img code with your text in your post and poof..there it is.