I think what you need to do is reduce the resolution as compared to making the picture smaller....If you want the actual picture which gets posted to not include certain stuff then you should crop it....
Check out Photoisland.com ... they have free software on a rotating basis so you have to check often.. One of them is easy to use for the above mentioned processes....signing up is free...

If you leave it as a very big file and just link to it.. it really slows down those of us using a dial up modem... I have quit some threads after waiting 6 minutes for it to load... so 'web resolution' is a better deal....