I’m using 10.4 and really need to update. But I don’t know what to do. I really only save photos, but i have photoshop and don’t want to lose that either
That's real old. Some older Macs can't upgrade from Tiger to Mavericks, because the hardware is too old. I'm in that position with a couple machines in the family. Check the specs of what you have.
Having said that, get a spare external portable hard drive and clone your internal hard drive. They're real cheap these days. If you really want to do your machine justice, spend a little more and get a larger solid-state or hybrid hard drive. Your machine will run many times faster and have more storage space. Clone your internal to the new one with copying software (easily available). Then swap the new one in place of the old hard drive, placing the old drive in the portable enclosure.
Now you can try installing the new OS X and see if it works out for you, and your critical apps still function. If not, you can boot off the external portable (look up the commands to do this) and access your old Photoshop and photos. Remember to differentiate between the hard drives when it comes to accessing email, etc. What I do is turn off all other apps on the old drive except the one I need to access with the older OS X. That way, if you boot off the old drive externally you're not mixing up your data between that and the newer drive.