May I attempt to clear up this on-going problem of posting pictures. I know that I have had problems in the past, but I think I have it sorted out now. I use XP so I don't know about Vista.
But here goes:-
1- hover your mouse over the thumbnail of the pic you want to post and it will tell you how big the pic is. The one I have chosen is 2.3mb.
2- Bring up your chosen pic to "full screen" size.
3- On the "top bar" click on "IMAGE", run down the menu and then click on "RESIZE".
4- In the 2nd box down you will see 2 boxes connected with a lock, and another to the right. Click on that box until you see "Pixels". Leave it at that.
5- Ignore the box that says "Print Size".
6- Leave the box that says "Resample" as "smart-size" with a "tick" in it.
7- Leave the box that says "Maintain Original Print Size" without a tick in it.
8- Unless you really want to distort things, leave the "ASPECT RATIO" box with a tick in it.
9- Leave the "RESIZE ALL LAYERS" with a tick in it.
Now we can begin to get your pics to the 256kb demanded.
1- Just for starters, bring down (or up) the pixel count to 1000 and click OK.
2- Check the thumbnail to see what size it is, and then repeat the process by increasing or decreasing the pixel count. This takes longer to write than it takes to do. With a little experience you will very quickly be able to judge and then get the pic you want to post within a few kb of the desired maximum.