Solution:1
There are many reasons to do not upload images in your WordPress media library.
That might be the issue of permission of your directory or as you said you have given permission already then you should check you upload path.
There are also some other steps to check and solve your issue.
Please follow this link. It will guide you step by step process and hopefully work for you.
Solution:2
Before trying any solutions, you need to deeply understand the reasons why the WordPress Media Library doesn’t perform images.
The issue of not showing images in the WordPress library is typically caused by an incompatible or poorly coded plugin. Most plugin-related problems come from third-party software or accidental coding issues. Those can make your Media Library prone to bugs.
Failure to show images in the WordPress Media Library can happen on account of inappropriate themes. Worst of all, themes that don’t submit to the Media Library can threaten the website’s efficiency. It will interfere with the Media Library by removing images afterward.
Apart from plugins and themes errors, your Media Library isn’t loading owing to wrong file permissions. All the WordPress files are stored on your web hosting server, which requires a specific folder and directory permissions to operate. So, if it appears to have wrong file permissions, scanning or uploading images files on the hosting server will be prevented.
Now, we’ll look at 3 different ways to make your WordPress Media Library work properly.
As we covered, your premium plugins may not be suitable for your site and come into conflict with others. This prevents you from uploading or seeing any picture on your website.
Following are some simple steps to examine your plugins:
Step 1: Head to your WordPress admin dashboard and select Plugins. A list of installed plugins will be presented on your screen. Select all of them, then scroll to Deactivate from the Bulk Actions drop-down menu and click Apply.
Step 2: Remove the cache memory if you have installed a caching or performance plugin before.
Step 3: Return to your Media Library and check if it loads. To make sure it works well, let’s try to upload a new photo and check if you can see it perfectly.
Step 4: If the Media Library runs correctly, one of your plugins is the major cause of this problem. Then, you have to reactivate each plugin and examine the Media Library manually. Repeat this process until you find the plugin that makes the library stops loading. It’s time-wasting and boring, but it’s the only way to find the culprit.
If the problem persists once you deactivate all the plugins successfully, it isn’t due to plugin incompatibility. Let’s move on to another potential source of the problems: the themes.
First off, go to Appearance > Themes to install and activate a new theme (a different theme rather than the one you’ve currently set). If your Media Library now operates, the theme might be the issue. Otherwise, it comes from a more extensive problem.
Since both plugins and themes play a vital role in your blog site. You have to look for an alternative immediately after you come across the issue.
Last but not least, another suspect for not showing images in the Media Library derives from invalid file permission if there is no problem with your plugins or theme. So, you need to set correct file permissions to resolve not showing image issues on your WordPress site.