How blind are spiders?

Ok, after all the advice i got I gave it a try.
Since my provider doesn't offer me logs I tried to work around this.
I searched a free webhost which can offer me logs, placed an image on it and placed a link to that image on my site.
Only drawback is that the image doesn't always show, well, in fact almost never.
You can find the image on my site http://users.pandora.be/jef_patat at the left bottom corner next to the nedstad image.
I tested it and I can see myself visiting my page in the logs http://jefpatat.freefronthost.com/.
With a little patience I will hopefully see other people as well.

Remaining questions:

1. Still I'm not sure if I will be able to detect a spider on my page. Spiders are blind, they don't "see" images, i know that, but will they load the image or not, so will i see the spider in the logs of the free host if only my page is spidered? Is there a way to test this?

2. My pages are larger than 101K, the html is never larger than 25, the css 10 and in this css the backgroundimages are called which might take up to a little more than 200K. But if I remember well I read somewhere the spiders don't interprete the css so in fact all these images won't be loaded and my pages will stay under the 101K, which is good I guess.
On the other hand, if they are loaded, could the algorithm be thinking I'm spamming since all my text is written over images?

Kind regards, Jef