I found similar problems or annoyances with downsizing pictures and tried using an on-line picture storage system, (PostImage in my case, others use Image Shack etc) which worked just fine. These have simple image downsizing systems, and rather than just using a resizing system and then the forum's uploading system, it should be easier to use one system only.
Also the "preview" facility on Roaring Season allows you to see(and fix) any mistakes or mis-hits without sharing them with the world.
Stu