[ubuntu-uk] HTML images

[John Davis]

Hi,

I am a novice  at web site design.

I am designing a web site for my son's business.

One page of index and 2 pages of photos. Portfolio pictures etc.

I have done the first and second page, in Firefox they display perfectly 
but with explorer and chrome, some of the photos are missing.

I have checked the naming conventions of the photos, some are initials I 
have made up and some are called DSCF3.jpg and some are csl1.jpg (example)

I have used this convention and viewed it with various browsers, some 
with the capitals display and others do not ,

Can anyone explain what is wrong ?

Help gratefully received,

John Davis