Q: I have an iPhone 6 that has no storage left for photos. To avoid paying for extra photo storage space on iCloud, Apple's online service, I tried to copy my iPhone photos to my computer. But I discovered that I can only copy the last three years of photos. What's wrong?

Ann Lang, Coventry, Conn.

A: The older photos aren't on your phone, but there's another way to recover them.

Why are the older photos be missing? You have probably turned on "optimize iPhone storage" in your phone's settings. (See tinyurl.com/y2njz5mn and scroll down to "Store your photos and videos in iCloud.) If your iPhone runs low on storage space, the optimize feature automatically uploads the oldest photos from your phone to your free 5 gigabytes of iCloud storage space, then deletes those older photos from the phone. Newer photos remain on the phone.

You wouldn't know this has happened, because when iCloud deletes older photos from your phone it leaves behind "thumbnail" versions of the pictures that appear in your camera roll. It isn't until you try to transfer those old photos to your computer that you discover they are missing.

This also causes another problem. The optimize feature has been working so long that your 5 gigabytes of iCloud storage are filled up with old photos. That means the optimize feature can no longer offload pictures from your phone to iCloud, and that has caused your iPhone to run out of storage space.

But you can solve all these problems. First, copy all the newer photos from your phone to your computer. After you have done that, delete those photos from your phone to free up storage space. Now download all your older photos from iCloud.com to your iPhone (see tinyurl.com/yxa7efs6 and scroll down to "Download photos and videos"), copy them to your computer and then delete them from your iPhone. Depending on how many old photos you have, you may need to do this more than once.

You now have all your photos stored on your computer, your iPhone has plenty of storage space available and your iCloud storage space is empty (everything deleted from the phone is also deleted from iCloud). The empty iCloud space will enable "optimize iPhone storage" to work again.

Q: My Toshiba laptop has bubbles in the liquid around the edge of the screen. In addition, two black and three red vertical lines have appeared on the screen. What can I do?

Mary Johnson, Moorhead, Minn.

A: The bubbles indicate that the screen's seal has broken, and that air has become trapped between the screen's glass outer layer and its LCD (liquid crystal display) inner layer. The only fix for that is to replace the screen ($60 plus the labor to install it).

The vertical lines could be caused by outdated display driver software, which helps the screen "talk" to the PC. Go to tinyurl.com/y5atppg2 and download the free "Driver Update Utility for Toshiba."

The lines also could be caused by a flaw in the $10 cable that connects the laptop's screen to the PC's main circuit board. The cable can become worn or cracked near the hinges that allow you to open and close the laptop. Have a repair shop check the cable.

E-mail tech questions to steve.j.alexander@gmail.com or write to Tech Q&A, 650 3rd Av. S., Suite 1300, ­Minneapolis, MN 55488. Include name, city and telephone number.