If you change the blog, e.g. remove a picture, it will change in all blogs. There is an easy solution.
In the blogs/skins/ directory create a new subdir, e.g. nautica_2lb. Copy in this directory all the contents of the original nautica_2l directory. You now have two identical skins. In the _main.php file of the nautica_2lb directory you can delete the picture. Now the skins are not identical anymore.

The setup for your blogs (Backoffice -> Blog settings -> Blog A -> Display) whre blog A is a variable for the blog name, you set the default skin for any of the three blogs. You probably want the skin selection turned off.

Good luck

yes, i did try to do a new directory in the skins folder and copy the content. but when i would set one of my blogs to the new directory, and try to view it, it would error out and say i don't have the properties setup correctly. any ideas? do you want to see a sample?

Don't panic. The blog is available under this link: http://akministries.org/m3t7zi6/index.php?blog=3&skin=nautica_2l. You see what I added: &skin=nautica_2l.
If you want this changed, you should dive into the stub file. http://manual.b2evolution.net/Stub_file is a link to the manual. If you still got questions, don't hesitate to ask.

Good luck

Are you refering to the banner_mountains.jpg image at the top of the blog? If so you can swap it out very easily for blog #3 without creating a different skin. In your Blog settings tab select blog #3 then the "display" subtab and enable "Allow customized blog CSS file". Now upload the image you want in that place as, for example, "style.jpg" to the media folder for that blog. You can do that selecting the Files tab then clicking the folder for that blog. Now upload a custom style sheet named "style.css" that contains the following:

#header {
background: url("style.jpg") top center fixed;
}

You might have to do a CTRL+Refresh to see it take effect, but the end result will be that your blog-specific style sheet will over-ride the skin's style sheet.

It's groovy!

Posting at the same time I see. This blog doesn't look like it's using stub files, so moosechic you can set your skin on your Blog settings tab. Pick the skin you like (nautica_2l I guess), and upload 2 files to your media folder for that blog. All your blogs will work properly, and you'll have a custom image where the stock "mountains background" image is on blog #3.

thank you everyone. i think i'm on the right track now. all seems to working well. appreciate everyone's help. :)

moosechic. i have followed the steps everyone has outlined on helping you with this issue, but i am still unable to make this work.

i have created a custom .css, placed it in the media file area, checked the box on blog settings > display, but still nothing.

any info would be great

nevermind. i didn't realize until i just saw it in the code, that the css has to actually be called "style.css."

newbie, out.