Sorry for adding yet another post onto this thread, but I realized I had forgotten to add WHY this was a good idea. (Don't see how to edit my post so I could add new information either!)
In any case, the reason I'm suggesting to opt with the customized header code over simply inserting an inline image tag is that you may wish to change that image over time. Provided the 'new' image uploaded to the server has the same size (width & height) as the old, and uses the same file name, you don't need to re-do the web code at all! (Be sure to use different filenames for the images store on your own system so nothing is is lost.)
Another reason why this is a good idea is that many wish to incorporate code for online advertising campaigns into their template. (Not sure if your site falls in that category, so this may not apply.) Again, very specific code needs to be included in the template so the money earned can be paid.
Opting for separate code for the custom header and footer will often save someone a great deal of time when doing updates for Coppermine. Not that there have been any radical changes in template structure in the past several versions, but who knows what the future holds? It is simply better to take the long view on things and separate that code as much as possible from the template so as to save time in the future. Just be sure to keep notes about what changes you've made in the template files, so duplicating them - if need be - within future versions of Coppermine will be a snap!
Hope I'm making better sense now!