How can I transfer a photo from my PC to my Android and make it my wallpaper?
Harry, you could choose to transfer the photo you wish to use in multiple ways. You could e-mail the photo to yourself and then save it on your device. You could connect your Android device to your PC with a USB cable and transfer it that way. Click here for a helpful article on connecting your tablet to your computer.
You could put your photo into a cloud account like Dropbox  or the Flickr photo site and copy it to your device from there.
Once you have the image on your tablet, you’ll want to go to settings on your tablet. This process could vary a bit from device to device, since every Android device is just a little bit different, but you’ll get the general idea.
Under Personalization, you’ll want to select Display.
Then choose Wallpaper.
You should see the option to select wallpaper for your Home or Lock Screen or for both. Select where you want to change the wallpaper.
Now you’ll get the option of where you want to look for your photo. Your photo may be in your Gallery in a downloads photo or in your picture folder in File Explorer.
Check the folders to find the image you wish to use.
You should see a preview of what your wallpaper will look like. If you’re happy with it, choose save.