When uploading photos, Firefox is not Showing the last folder used

When uploading photos, Firefox is not Showing the last folder used. Normally, when uploading a photo from a certain folder, the next time you do that, the same folder shows up unless you choose a different one. Now, it keeps going to one specific folder even though I uploaded from a different folder previously. Example: say I uploaded a photo from my folder "sympathy pics". Then I upload a photo from "my documents". The next upload pop-up box still pops up the "sympathy pics" folder when it should bring up "my documents". Can someone please help me?