Which browser are you using?
Could be from your hosts file?
If using Mozilla Firefox, could be from using NoScript.
Also could have the images being removed from using Adblock.
Tell us which browser you are using and we'll try to hel you find the culprit.
Did you try checking your mail using another browser?
Recently, I have been receiving email differently. Where I used to receive everything in html, now much of my email comes differently. I will see urls instead of a full screen. Picking one url might give me a portion of a logo from the screen I'm used to seeing. Furthermore, email from one source might be received as normal, while the next may come in the above mentioned form. Ubid is an example... I may receive a normal email today, but tomorrow is will be like a text version with a number of urls that don't take me anywhere? Any ideas of what might be going on?
My system is a home built P4 3.07 Intel running XP Pro (SP2) with 2 Gb memory, 1.5 TB storage, Office/Outlook '07, system is checked weekly for malware.