1) you already have your pics in either your, my pictures or my documents....so that takes care of that step....
2) you can edit the size really easy...get the picture up on the screen....right click the picture and click edit.....there will be 4 or 5 choices on the top left (should be)
3)click image and then click stretch and skew.....
4)when the next screen comes up you can change the 100% values on each to any value you want....a good place to start is w/60% in both of the boxes for stretch.....click save.....

now you can go to the desired web site and start a new post or add too a current one.....

lets just use 3-dshoots.com for a second....

Click start a new thread in the section you want the pics in....now the screen comes up where you type in what you want to say....this part you know how to do....

you can put words in there if you want...... before you click post reply, you need to scroll down a little bit to where you see additional options, its right under the submit reply or preview post.....

you will see a box that you can click that says manage attachments, click on that....

a new window will pop up and it will have near the top a open box that says "upload file from your computer" above it in small print

next to that are 2 boxes that say, browse, then the next says upload.....

click browse and go get your pic from the file that is saved in your computer, double click the picture you want to post...

it will show up in the upload file from your computer box, now click upload.....it will show you some little green uploading box, wait till it is done loading, you may need to resize again if its still too big.....if not go to the next step.....

there will be a place that says attachments.....now click close this window....now go ahead and click submit reply.....it will post your reply and your pics.....

it sounds like alot but really after you do it 2 times you going to say wow this is easy....

I really hope this helps.....and I promise it looks like alot to do but when you got your first bow, gun, car, chainsaw, or atv, it looked like alot of things to remember right?? well after you did it a couple of times it was like second nature.....