One way is to rename it. If it is only used on one page this is probably the easiest way for a one time fix.
If you change the image frequently you could use the <HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE"> tag so that users never cache the page or pages it on (but check out http://support.microsoft.com/kb/222064/ )
[quote=bjornenki;360150]One way is to rename it. If it is only used on one page this is probably the easiest way for a one time fix. /QUOTE]
Yes, I agree. In that case you should change photo's filename and update your HTML/CSS code with new filename.