Alexandru Vornicescu

If you want to download external images in your posts automatically so the page will use local image files instead of external image files then this plugin can help you.
<iframe loading="lazy" class="youtube-player" width="750" height="422" src="https://www.youtube.com/embed/1dZZ5ucNlQY?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent" allowfullscreen="true" style="border:0;" sandbox="allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox"></iframe>
It will replace the URLs of all external images (if the image has a different host URL) in your posts.
The URLs will get replaced with a local image copy URLs.
The action will be made on the post/page preview, not in the admin Edit page or after post save.
All the images that will be saved to your uploads folder (wp-content\uploads), not to your Media Library page.
This plugin can make your work faster if you like to use external images from other sites and you would like not to lose times on uploading images into you library every time for every image.

Download External Images In Posts

IT WORKS

This is the worst concept I have ever seen. This plugin should be reported.

I don't know what is the main concept of the plugin is. If you enable this plugin and start working with it, it downloads 1 content 100th of times or every time when someone visits the post. Even it consumes storage because everytime someone visits, first the plugin downloads and files to internally and then serve.

Within the middle of the time, visitors need to wait for the download and serve the content.

Therefore, SORRY TO SAY BUT, THIS IS A FLOP PROJECT.

Worst concept - Advising to not to use

This plugin will download external images in your posts to your "wp-content/uploads" folder.

Fabian

Traffic Limiter is a useful addon for blogs with many media files which can cause high data traffic. 
There are three traffic limits to avoid over traffic costs: daily, weekly and monthly limit. If one of these limits is exceeded downloads will either be redirected to a custom URL or a custom message is displayed. For images you can define a fallback icon which is displayed instead of the message. Additionally a download bandwidth can be set for registered users and guests.
Also included is a statistic system which displays the current traffic consumption and individual file stats to see which media produces the most traffic.
All files are sent to the browser by a PHP script, supporting the most HTTP headers like <code>If-Modified-Since</code> (for caching) and <code>Range</code> (for partial downloads)
If the Apache extension <code>mod_rewrite</code> is installed download links stay the same, if not links to media files are automatically redirected. It is recommended to install <code>mod_rewrite</code>, although this plugin works without this extension.
Note: If you provide lots of downloads or media files you should try my download manager <a href="https://wordpress.org/extend/plugins/wp-filebase/" title="WP-Filebase" rel="ugc">WP-Filebase</a>.

Traffic Limiter

Limits traffic and download bandwidth of media files. Additionally this plugin includes a download statistic system.

Download External Images In Posts vs Traffic Limiter