MicrostockGroup

Hi,
    I'm new to this forum but it looks perfect for my needs and there seem some very useful aspects to it.
I have recently started uploading stock pics but kind of hit a brick wall.
I have the 30 day trial of photoshop cs3 and have been using the quick selection tool on some flower pics and then using the feather tool etc to smoothe them down.
I was wandering if there's a way to smooth the edges manually when you go down the 1 or 2 mp without the lines still being "jerky" or over-compensating your work?

It's an automatic Pentax A30 but usually the stockphoto site have no problem with this.The pics are jpg but taken WITH backgrounds as instead of white

Cheers