Because some members have been hitting the file size limit when uploading, the max picture size has been increased to 1.5MB (was 256KB). The total picture storage you can have on the board at any given time has also been increased to 10MB (was 5MB).
To manage your uploaded pictures, click on your handle (member name) at the left of one of your posts while logged in. This will open your member info page. On the lower right you will see a box that says "Upload Quota" and displays how much of your limit has been used. Under that box is a link that says "User Attachment Control Panel", click this link to delete old images. Deleting old images frees up space for new pictures to be uploaded.