I was looking through pictures on my tablet

Hi Georgia Griffths,

Find the cause

All kinds of problems could be making that file refuse to open. Maybe the file has become corrupted, or someone saved it in an incorrect format, or you're simply opening it with the wrong program. A bit of detective work at the beginning can help you work out what the problem is. From there, you can choose the best way to solve it.

The message you see when you try and open the file will give you some clues. If you double-click on an item that's categorized with an unrecognized file type, a Windows computer will ask, "How do you want to open this file?" and a macOS machine will say, "There is no application set." Both operating systems will then give you options for finding applications that can open this mysterious format. Within a specific program, if you try and open a file that the software can't read completely, you might see messages about unreadable content or invalid file types. This confusion could indicate that the file is corrupted or has the wrong file extension added to it.

If you're not sure what kind of file you're dealing with, a couple of online tools can help. CheckFileType and Online TrID File Identifier both let you upload a file in your browser and then identify the mystery item. Once you know the file type, you can find a program capable of accessing it. As always, be wary of opening files you aren't sure about or that have come from suspicious sources.

Change the file extension or format

A file extension is the three or four-letter code after the dot in its name. For example, a musical file's extension will be the ".mp3" that appears at the end. Some files show up without these codas, but you can force them to appear. On Windows, go to Windows Explorer, navigate to the View tab, and tick the File name extensions box. On macOS, choose Finder then Preferences, go to the Advanced tab, and tick Show all filename extensions.

A file's format is the way it was encoded or saved to the disk—as the aforementioned MP3 file, or a PowerPoint presentation, or a video. The file extension described above acts as the signifier or label for the file format, so these two must match up. 

Otherwise, you're going to run into problems when opening files. 

To change a file extension on Windows just click on the file and edit the last three or four letters to show the correct extension for the format.

Modifying the extension doesn't actually change any of the file's contents, but it can make a file recognizable to the applications on your system, thus helping you open it. For example, your image editor may not know what "picture.ipg" is supposed to be, but it will open "picture.jpg" with no problem. If the file extension has been mislabeled for whatever reason, then editing it creates an easy fix.

Hope this helps 

Below you may find guide, which I found in Google on query adobe photoshop recovery. Moreover some useful articles and resources, just try, one of them might aid https://helpx.adobe.com/photoshop/kb/file-recovery-photoshop.html

Another long-shot technique in Windows is to see if there's a ShadowCopy of your file (copy from a restore point). Right-click on the file, choose Properties from the list - in the Properties box, choose the Previous Versions tab. Hopefully (in theory…) there'll be a useable previous version to choose from. These instructions are for Vista. If the tab is not there, do a search for instructions for this feature on your operating system.