It’s the same thing every vacation: The photo collection grows and grows and grows, with dozens of photos being added every day. The easiest way to back up your photos is via cloud storage; you can then store them in Apple’s iCloud, on Google Drive, Microsoft OneDrive or in the online storage of a third-party provider.
However, this is only a temporary solution, because after your vacation you should review the pictures on your home PC, sort out duplicates and unsuccessful ones, and edit the others if necessary.