i hope jim does not mind me sharing this.
Nearly every picture that was uploaded to our site since 1996 is still on one of our servers. All of those will display on the appropriate page. The missing pictures were uploaded to 3rd party hosts like ImageShack, PhotoBucket and others. Most of those hosts will delete images off of their servers after a period of time. Oldgas.com has only deleted images in a small handful of cases, usually involving copyright or privacy issues, never to save money or free up space. Our current File Manager upload process is set up to keep images online as long as the site is online. Over 120,000 images have been uploaded via File Manager to Oldgas.com in the last couple years.

When you see the "X" or empty box for a missing image, right click on it and choose "Properties" or "View Image Info" to see the .com address of where the image used to be. Sometimes there is no placemarker for a missing image, so the original host would be more technical to figure out.

The large numbers of images and other files are part of the cost of the site. But the largest cost factor is the number of simultaneous processes requested by many users. The oldgas.com server gets over well over 150,000 page view requests per day with a dozen or more processes involved in each page view. The server is equipped with its own dual core Xeon processor, solid state hard drives and fiber optic to the Internet. Look at the fine print near the bottom of forum pages to see the speed and processes involved for that page, such as:
"Generated in 0.026 seconds in which 0.010 seconds were spent on a total of 17 queries"

It is annoying that so many older valuable topics have images that are missing. If I would have known years ago that the free image hosts would delete images, I would have started archiving those images to keep copies on our servers. You may get lucky and find some of those old topics have been archived with images at The Internet Archive Wayback Machine:
https://web.archive.org/web/*/http://www.oldgas.com