Came across with the jpeg error in which jpeg image shows grey area at the bottom. The image appears useless to your personal photographic collection. But owing to its importance, you do not want to lose the photo. Wish to keep the pristine image in your album.
Good news, you can get back the image either rectified in totality or in humble resolution but without loss of integrity. As you know jpeg file store data in two parts, the first part is jpeg header and the second part is jpeg scan. Alteration in either in the header or the scan data makes the image corrupt; consequently, photo viewing app throws jpeg error. Some of the common reasons for jpeg errors are as follows:

• jpeg header information is not added by camera due to an improper saving of the image to the memory card
• jpeg image is corrupt during file transmission from camera’s memory card to computer or other storage medium
• jpeg image is corrupt after recovering via photo recovery software, thereby making the recovery useless unless it is repaired.

If your image file contains incomplete jpeg scan information, then the image will have grey area after a particular point as shown in the figure. This happens as the progressive scan information of the image is perfect till that point and corrupt afterwards.

Corrupt Image with Grey Area {Tentative Figure}

Repairing a corrupt jpeg file is mandatory to maintain its visual fidelity. Sometimes even extracting the thumbnail information can be very useful. Thumbnail is the smaller resolution of the same image stored in the file’s header to provide faster preview.
In case of jpeg file with corrupt jpeg scan, its header information can be used to fetch the thumbnail image. The manual method to fix the grey area in the image is as follows:

1. Use a hex editor to open the corrupt jpeg file with grey area
   Note: A hex editor is a binary file editor of the computer program that allows manipulation of the fundamental binary data. With a hex editor, a user can see or edit the raw and exact contents of a file, as opposed to higher level application software.
2. Use the same editor to open an error-free jpeg file created from the same camera
3. Extract the thumbnail data present in the header of the jpeg file basis the perfect
4. Save the thumbnail information to get the same image in lower resolution

The preceding manual method is suitable for advanced users. You, instead, might prefer a powerful image repair software that rectifies the image without any technical know-how. All you need is the right jpeg repair software that can handle any kind of jpeg error.
The software method to fix the grey area in the image is as follows:

• Download Stellar JPEG Repair software on your computer
• Install the software by double-clicking on the software’s .exe file
• Launch the software by double-clicking the software’s icon present on the desktop
• Click on the ‘Add File’ option to add the corrupt jpeg file(s) with grey area
• Check the ‘Select All’ checkbox to pick all files for repairing
• Click the ‘Repair’ button to start the repairing process
• Select any repaired file to preview on the right pane
• Click the ‘Save’ button to save the repaired file

You can use the software to add or rectify jpeg header, extract thumbnail in case of severely corrupt jpeg scan, repair corrupted jpeg photos recovered using data recovery software, etc.

Synopsis
The blog indicates the jpeg incomplete scan error where grey part is present in the jpeg image. As a manual method, you can use a hex editor to extract thumbnail from the header of the corrupt jpeg file. The usage of the hex editor requires advanced understanding of how jpeg header is generated and stored, which can help you to repair corrupt jpeg image. In case you need easy and sophisticated method, you can definitely use Stellar JPEG Repair software to repair your damaged jpeg files and extract thumbnails.