Server not detecting image files without extension - Need help to add MIME Types

Uploaded my website to hosting server - it has code where it displays some image files without extension.

The images should be jpg.

eg. <img src="./images/popular/2012logo-thumbnail"

the jpg is on my server as 2012logo-thumbnail (no extension)

I want to keep the file names and links as they are however I understand that I need to add mime types (or something) to my server file - (apache) maybe htacess file.

Hope this makes sense.

I am aware that this is very simple for someone who know what to do - however I am offered £4 - £10 per hour for what I believe is 5 mins work.

Please bid - I need help asap.