Welcome to Android Central! Are you talking about transferring photos that you took with your phone's camera onto the SD, or photos from your computer onto your SD?
There are a couple of different ways to transfer photos from within your phone to the SD card. You could install a good 3rd party file manager app like or (I'm not familiar with the One VX, so I don't know if it comes with one preinstalled), then navigate to the folder with your photos from the camera--it'll be something like /storage/sdcard0/DCIM/Camera. You can then select the photos you want to copy, then select the target folder. For older Android versions (i.e., prior to Jellybean), the external SD card will be /storage/sdcard1. You might need to create a target folder, like "My Pictures," so that you'll be moving the files to /storage/sdcard1/My Pictures.
Another way to move files around would be to plug your phone into your computer via USB, and access the files using Windows Explorer. That way, you can drag and drop files easily, and it's also easier to multi-select, if there are a lot of files to move.
If you want to move photos that are on your computer onto your SD card, the easiest way would be to unmount the card from your phone (in Settings/Storage), remove it, insert it into your computer, then transfer the photos.
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