Hi,
Please review the functions.php file around line 296 it shows the 12 image sizes that the theme creates and the description for each:

$avia_config['imgSize']['widget'] 			 	= array( 'width' => 36,  'height' => 36 );						// small preview pics eg sidebar news
$avia_config['imgSize']['square'] 		 	    = array( 'width' => 180, 'height' => 180 );		                // small image for blogs
$avia_config['imgSize']['featured'] 		 	= array( 'width' => 1500, 'height' => 430 );					// images for fullsize pages and fullsize slider
$avia_config['imgSize']['featured_large'] 		= array( 'width' => 1500, 'height' => 630 );					// images for fullsize pages and fullsize slider
$avia_config['imgSize']['extra_large'] 		 	= array( 'width' => 1500, 'height' => 1500 , 'crop' => false );	// images for fullscrren slider
$avia_config['imgSize']['portfolio'] 		 	= array( 'width' => 495, 'height' => 400 );						// images for portfolio entries (2,3 column)
$avia_config['imgSize']['portfolio_small'] 		= array( 'width' => 260, 'height' => 185 );						// images for portfolio 4 columns
$avia_config['imgSize']['gallery'] 		 		= array( 'width' => 845, 'height' => 684 );						// images for portfolio entries (2,3 column)
$avia_config['imgSize']['magazine'] 		 	= array( 'width' => 710, 'height' => 375 );						// images for magazines
$avia_config['imgSize']['masonry'] 		 		= array( 'width' => 705, 'height' => 705 , 'crop' => false );	// images for fullscreen masonry
$avia_config['imgSize']['entry_with_sidebar'] 	= array( 'width' => 845, 'height' => 321 );		            	// big images for blog and page entries
$avia_config['imgSize']['entry_without_sidebar']= array( 'width' => 1210, 'height' => 423 );					// images for fullsize pages and fullsize slider

so depending on the elements that you are using you can decide to remove some of these, if you which.
WordPress adds 4 other sizes, small, medium, medium_large, large, and other plugins may add other sizes, such as woocommerce.
Removing these sizes will depend on your site layout and the devices that people use, you will need to test and decide if you need these sizes. Removing some sizes will make your site use larger images than needed which could slow down your loading time, or on very large screens some of your images may seem to be blurry because a smaller image is used. So there is no quick answer, you will just need to test.
You may also note that the thumbnails that WordPress creates may be larger than the original, so 30k of images might be over 9 gigs, here is a easy way to compress 30k of images down to under 900 mb without a plugin and save a lot of space.

Best regards,
Mike

Hi,
Glad we were able to help, if you have any further questions please create a new thread and we will gladly try to help you. Thank you for using Enfold.

Best regards,
Mike

Hi,
Glad Ismael could help, if you have any further questions please create a new thread and we will gladly try to help you. Thank you for using Enfold.

Best regards,
Mike

Hey dweddell,
Thank you for the link to your site and your screenshot, try adding a max-width: 33%; to each of your three elements for mobile like this:

@media only screen and (max-width: 767px) { 
	.responsive #top #header #header_main .inner-container .main_menu {
    order: 1;
    flex-basis: auto;
    align-items: center;
    align-self: center;
    height: inherit !important;
    width: 33%;
}
.responsive #top #header #header_main .inner-container .logo {
    order: 2;
    flex-basis: auto;
    min-width: 100px;
    z-index: 9;
    transform: translateY(30%);
    margin-top: -30px;
    max-width: 33%;
}
.responsive #top #header #header_main .inner-container .widget {
    order: 3;
    flex-basis: auto;
    padding: 0;
    clear: none!important;
    justify-content: center;
    align-self: center;
    align-items: center;
    z-index: 1;
    max-width: 33%;
}
}

This is the expected results:

Best regards,
Mike

Hi,
Thanks for the link to your page, the first video element (not the code block) has the correct link format youtube.com/watch?v= and when I test it on my site it works correctly, please see the link in the Private Content area.
Try disabling all of your plugins. If that resolves the issue, reactivate each one individually until you find the conflict.
I’m seeing these errors from your site but I don’t know what could be causing them, perhaps a plugin.

Best regards,
Mike

Hi,
On the most part that is correct, we don’t have a list it depends on the elements that you are using.

Best regards,
Mike

Hi,
Glad to hear that you have this sorted out, if you have any further questions please create a new thread and we will gladly try to help you. Thank you for using Enfold.

Best regards,
Mike

Hi,
Glad Ismael could help, if you have any further questions please create a new thread and we will gladly try to help you. Thank you for using Enfold.

Best regards,
Mike

Hi,
You would need define each one separately, there is not a way to change the setting for all elements because each element has the media query added in it’s CSS.

Best regards,
Mike

Hey Yory,
I recommend using the WordPress ▸ Tools ▸ Export ▸ All content and use the xml file to import to your new site, note that you will want your old site to still be live when you import into the new site as the new site will import the images directly from the old site.

Best regards,
Mike

Hi,
Glad to hear that you have this sorted out, if you have any further questions please create a new thread and we will gladly try to help you. Thank you for using Enfold.

Best regards,
Mike

Hi,
Glad we were able to help, if you have any further questions please create a new thread and we will gladly try to help you. Thank you for using Enfold.

Best regards,
Mike

Hi,
Glad that this have helped, I only added a new child theme.
I don’t know what was wrong with your old child theme as I didn’t see any issues in it, I believe that this points to a caching issue.
Nonetheless with the new child theme you site now doesn’t have the error, so I imagine that we close this thread then?

Best regards,
Mike

Hi,
Glad we were able to help, if you have any further questions please create a new thread and we will gladly try to help you. Thank you for using Enfold.

Best regards,
Mike

Hi,
Above you wrote that the site was created by a guy 7 years ago, are you sure that you purchased the theme, or was it him? If you had purchased it, you would see it in your Theme Forest account. You may need to purchase the theme though your account so that you will be able to update your site now and in the future.
I believe that host gator offers the staging site option, so you should ask them how to use it, and also ask them how to backup your site and restore it, so if anything goes wrong you can restore your site.
I don’t recommend using backup plugins, the webhost server backup is always better and more reliable.

Best regards,
Mike