Most people use this...
Just sign up for an account and upload your pictures. Then there will around 4 types of links you paste in. Copy the code for forums and paste it in your reply. That will automatically show the picture.
NOTE: It isn't the DIRECT LINK to the photo, the vbcode/forum one.
Oh and make sure you re size your photos before posting if they are too big.
You can re size them in Photobucket.