Sure, that's what attachments are for - in the main post page, select 'Attachments and other options' and you'll find an upload box there.
I've tried that, but it's an attachment only. I want to include the photo into the post itself, and then wrap the text around it. If I could upload the file from my computer and have it inserted into the post, or even copy and paste it into the post, that would be what I am looking for.
Wrapping text around an image, look for the float mods on the mod site.
I found "Float_BBCode", but when I tried to install it, I get an error message that's incompatible or corrupted. Do you know of one that works?