JPEG Medic // Accurate Manual JPEG Recovery
Table of Contents
  1. Overview
  2. Theory of JPEG Repair
    1. JPEG structure
    2. How to fix broken JPEG file
  3. Working with the Program
    1. Main menu
    2. Virtual folder tree
    3. Files panel
    4. Preview panel
    5. Cluster view
    6. Hex view
  4. Repairing JPEG image
    1. Opening JPEG file
    2. Repair window
      1. Menu commands
    3. Repair procedure
      1. Visual analysis and localization of damaged MCUs
      2. Finding the next correct MCU
      3. Deleting damaged MCUs
      4. Inserting empty MCUs
      5. Color correction
        1. Automatic color correction
        2. Manual color correction
      6. Filling empty MCUs with data
        1. Use the thumbnail image to fill the empty MCUs
        2. Auto-generate missing content
    4. Saving repaired JPEG image
    5. Repairing fragmented JPEG file
    6. Repairing damaged JPEG image based on SOS marker
    7. Repairing JPEG file encoded by ransomware

Visual analysis and localization of damaged MCUs

Damaged MCUs are easy to localize visually. Typically, the image after the damaged MCU abruptly changes its color, or becomes grayscale, or looks like a mess of colors. For example:

Damaged MCU Damaged MCU

Here, we can clearly see where the damaged MCU is located. Directly prior to the damaged MCU there is the last correct MCU. Now we need to locate the next correct MCU to isolate the damaged part of the JPEG image.