I know quite a few people might struggle to post pictures on the forums so here is 2 ways to do it.
Method 1:
Head over to http://imgur.com/'>http://imgur.com/ (you do not have to make an account, don't worry). Click the 'Computer' button (circled):
Select the images you want to upload and press 'Open' (circled):
A box will summarise what you want to upload and give you the choice to add more images if you need to. Once ready press 'Start Upload' (circled):
The image(s) you select will get uploaded, when they are finished you will see this screen. Copy the 'Direct Link (email & IM)' text:
Come back to your post on the forums and click the Image button (circled):
Paste in the direct link you just copied and press 'OK' (circled):
Done, the image will appear in your post in full size:
Method 2:
Make sure you have pressed 'Use Full Editor' if making a post, if making a topic you don't need to worry about this.
Click 'Choose Files' (circled):
Select the images you want to upload and press 'Open' (circled):
Once the upload is complete, you can submit your post. The image(s) will show up as a thumbnail at the bottom of your post which people can enlarge by clicking on:
If you're still having issues then PM me, but please have given both the above methods a shot because they are very easy.