Picture sizing trouble

Today, without me doing anything, something happened to some lastFM code I had put in a text widget, the lastFM box was resized and much smaller than it shuold be. Same happened with a pic I have, also in a text widget.

I didn’t think mych of it, until I tried to fit an image into my latest post. The img size was 500×183, but WP kept resizing it and making it much smaller than it should be. I tried changing it in the code editor, but the code auto changed. I resized the pic to 450 in width, but then it showed up as 384 x something.

I’m using the theme Ad Clerum 1.0 on WP 2.3.1, but I haven’t made any modifications to the code that could create these oddities.

Anyone experienced this and/or have a solution to it?