Blurring thumbnails in Xiaomi Redmi Note 7: 7 reasons and 5 ways to fix

The Xiaomi Redmi Note 7 is still one of the most popular budget smartphones due to its price-performance balance, but many users face an annoying problem: the thumbnails of photos and videos in the gallery are displayed blurry, although the files themselves look normal when opened, a problem that can manifest in both the standard Gallery app and third-party file managers.

Unlike hardware defects in the screen or camera, sketch blurring is a software error related to cache, MIUI compression algorithms, or application conflicts. In this article, we will discuss the 7 main reasons for blurred thumbnails on the Redmi Note 7 (including the Pro and Global models), and we will give 5 proven ways to restore them – from simple cache cleaning to manual editing of system files.

We will focus on the nuances of MIUI 10–14 firmware, as the algorithms for generating sketches changed with each major update, and consider why the problem may come back after a reboot and how to avoid it.

1.Why miniatures become blurry: technical reasons

The blurring of sketches is not an accident, but a consequence of the operation of the optimization mechanisms of MIUI.

• 🔹 Aggressive cache compression: MIUI It automatically reduces the resolution of thumbnails to save memory, but sometimes the algorithm will work too hard, especially on devices with almost full drive.
• 🔹.thumbnails file corruption: The system file that stores sketches can be damaged if the power is suddenly turned off or the Gallery application crashes.
• 🔹 Cloud Services Conflict: Sync with Mi Cloud or Google Photos sometimes leads to low-quality previews.
• 🔹 File system errors: Redmi Note 7 with eMMC 5.1 memory may have delays in reading metadata, causing artifacts in sketches.

Interestingly, the problem is more common on global ROM devices than China ROMs, which are due to differences in memory optimization algorithms: in Chinese versions, thumbnail cache updates less frequently, but also takes up less space.

It is also worth noting that blur can be selective: for example, sketches of HEIF (.heic) photos are blurred more often than JPEGs because of the additional decoding layer.

2. How to check if a hardware or software problem

Before you start fixing, it is important to rule out hardware malfunctions. Here are 3 tests that will help differentiate the cause:

1. Check on another device: Connect Redmi Note 7 to your computer and open files through Windows/macOS Explorer. If thumbnails are blurred and there is a problem in the files themselves (possibly they were saved at low resolution). If the PC sketches are clear, the firmware is to blame.
2. Test in Safe Mode: Reboot your smartphone in Safe Mode (press the power button → long press on "Stop"). If the thumbnails are normal in Safe Mode, the problem is in a third-party application.
3. Screen Diagnostics: Run the display test through the engineering menu (##289##). If the blur is only visible in the gallery and there are no artifacts in the screen test, it's the software.

Pay special attention to the file format: on the Redmi Note 7 thumbnails RAW-Photos (.dng) always show worse because of the limitations of the Snapdragon 660 processor.

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If blurring is only apparent for photos taken in 48 MP mode, try turning this feature off in the camera settings. The smartphone may not have time to generate full-size sketches for such files.

3. Method 1: Clearing the cache of the gallery and media storage

In 80 percent of cases, the problem is solved by a simple cache cleanup. There are two levels of thumbnail caching on the Redmi Note 7:

1. Cash of the Gallery annex:

Go to Settings → Applications → Application Management → Gallery → Storage → Clear the cache. After that, restart the device. Sketches will be recreated automatically the next time you open the gallery.

1. System cache of media files:

This cache is stored in /data/media/0/DCIM/.thumbnails to reset it:

• 📱 Use a file manager with root rights (for example, FX Explorer or connect to your PC via ADB.
• 🗑️ Delete all files in the.thumbnails folder (do not delete the folder itself!).
• 🔄 Reboot your smartphone.

If the thumbnails are blurred after cleaning, check the permissions for the Gallery app: go to Settings → Apps → Gallery → Permissions and make sure that access to the storage and camera is enabled.

Backup of important photos|Close all applications in multitasking|Connect the charger (the process may take place) 5-10 minute)|Check the free space on the disk (at least necessary) 500 MB)-->

Method 2: Re-creating a media database

If the cache cleanup didn't work, the problem could be a damaged database of media files. On Redmi Note 7, this database is stored in a media.db file and updated by mediaserver to recreate it:

1. Open Settings → About the phone and 7 times click on the MIUI version to activate the developer mode.
2. Return to the basic settings, go to Additional → For developers and enable debugging over USB.
3. Connect your smartphone to your PC and perform in ADB Command: Adb shell am broadcast -a android.intent.action.MEDIA_MOUNTED -d file:///sdcard/ This command forcibly initiates scanning of media files.

Alternative method (without PC):

1. Delete /data/data/com.android.providers.media/databases through the root-rights file manager.
2. Reboot the device. The system will automatically create a new database (it can take up to 15 minutes).

⚠️ Note: After the database is recreated, media data (such as playlists in a music player) may be reset, and gallery albums will be temporarily lost, and they will recover after a full scan.

5. Method 3: Disabling MIUI optimization for thumbnails

Starting with MIUI 11, Xiaomi added aggressive sketch optimization, which sometimes fails, to turn it off:

1. Activate the developer mode (as in the previous method).
2. In Settings → More → For developers, find the option Disable MIUI Optimization (or Disable MIUI Optimization in English firmware) and turn it on.
3. Reset the device.

If this option is not in your version of MIUI, you can turn off optimization via ADB:

adb shell settings put global miui_optimization_disable 1

This method also helps if thumbnails are blurred only in some folders (like WhatsApp Images or Screenshots).Once optimisation is disabled, the system will use standard Android algorithms to generate sketches.

6. Method 4: Manually changing the size of the thumbnail cache

By default, MIUI limits the size of the thumbnail cache to 50MB, which may not be enough for users with a large photo collection.

1. Install Activity Launcher from Google Play.
2. Find Media Storage Settings (or com.android.providers.media.settings) in it.
3. In the menu that opens, select Cache size and set the value to 200 MB or 500 MB (maximum 1 GB).

If Activity Launcher does not find the desired item, you can change the cache size via ADB:

adb shell setprop media.thumb.cache.size 524288000

Here, 524288000 is the size in bytes (500 MB). Once you run the command, restart the device.

⚠️ Attention: Increasing the thumbnail cache does not guarantee a solution if the cause is corrupted files or application conflicts.

7. Method 5: Alternative galleries and file managers

If standard methods didn't help, consider using third-party apps.The best options for the Redmi Note 7 are:

When using alternative galleries, turn off the standard MIUI Gallery to avoid conflicts: go to Settings → Apps → Gallery → Disable. This will also save battery life, as two media scanning services will not work.

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If you choose Google Photos, disable the option “Saving traffic” in the settings of the application – it forcibly reduces the quality of sketches when the Internet is slow.

8.Prevention: How to avoid repeated blurring of thumbnails

To prevent the problem from returning, follow these recommendations:

• 📁 Clean the cache regularly: Install the app SD Maid and set up automatic cache cleaning Gallery once a week.
• 🔄 Avoid abrupt power outage: Always use the regular shutdown button to avoid damaging.thumbnails files.
• 🖼️ Store originals in the cloud: Set up your photos automatically in Google Photos or Mi Cloud in their original quality, which will allow you to restore clear sketches when you crash.
• 🛠️ Update the firmware: B MIUI 12.5+ Xiaomi has improved the algorithms for generation of thumbnails. check the updates in Settings → The phone. → Updating the system.

If you reboot your smartphone frequently (for example, due to firmware testing), add a script to automatically clean the cache when you start.

1. Install Tasker or MacroDroid.
2. Create a task with the trigger "Boot system".
3. Add the action Execute the command with the text: rm -rf /data/media/0/DCIM/.thumbnails/*

On the Redmi Note 7 with firmware older than MIUI 12.0.3, the thumbnail blur may be due to a bug in the com.miui.gallery service, which Xiaomi officially recognized and fixed in the update from 15.07.2021 (V12.0.3.0.QFG). If your version is older, the problem is precisely software, not hardware.

FAQ: Frequent questions about blurred thumbnails