Changing the image sizes??

Hi all,

I upload images around 500×500, although this varies according to the original as I just batch resize by a percentage.

I thought WordPress created various sized versions but I can’t find a reference to them anywhere. I’m getting big fat warnings about images being resized. I see the images have two dimensions added to the end (WordPress default creations?). One is resized from 520×24 to 272×148, and the other is 160×160 to 80×80. The tool gives me a direct link to the files to download, so I resized all the 160’s to 80×80 and compressed them a bit more as you don’t need to worry too much about quality at that small a size.

The thing is, I don’t know where to put them. Do I have to navigate to the actual files and replace them? Surely WordPress offers a better way? I’m hoping that WordPress has a way to specify the specific sizes it creates, because obviously the ones that WordPress is creating don’t match the specs of my theme.

Also, if I can change it so the specific size versions are created, is there a way to have them compressed? I compress my files using a Windows tool (Caesium). It’s not lossless but still does a great job.

Thanks ??