Fixing Markup Errors due to Shortcodes in Wordpress

Question

Its me, the css / html fool again :D.

No joking - i got a few frustrating problems in numbers they are 5 as you can see here:

W3C Markup Validation

The first 4 of them are due to a shortcode i use its called "MD-Shortcodes" and a part of the Themesholic "Elite" Theme. Due to the fact that they got there own Markup i cant realy edit them in the Backend and i couldnt find something like a "part of html" file to edit those bugs.

The 5. Problem is very simple in the theorie.. its just a "alt="" " that is missing.. but(!) im using a plugin called "Nelio External Featured Image" to embed the always updating pictures from a website. I can just manage there Size based on @Media resolutions in css and because of that and the fact that i dont get the picture in my library im pretty sure its created by some sort of .php or stuff like that.

I have no clue about php so it would be very cool if someone could check the files and tell me what to change to add a empty alt tag .. after a reupload of the plugin it should work like a charm.

I really appreciate that you invest a part of your lifetime in helping people! Thanks :).

Edit:

I found this in the nelio-efi-main.php. Would it work if i simply add a alt="" at the end of the first line?

$html = sprintf(
    '<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" ' .
    'style="background:url(\'%s\') no-repeat center center;' .
    '-webkit-background-size:cover;' .
    '-moz-background-size:cover;' .
    '-o-background-size:cover;' .
    'background-size:cover;' .
    '%s%s" class="%s wp-post-image nelioefi" />',
    $image_url, $width, $height, $additional_classes );

Answer 1

I wouldn't recommend editing any of the files in the plugin as they will get overwritten when you update the plugin.

There might be a way to hook into that plugin by extending it, but I'm not familiar with it. If you contact the plugin's developer, they could probably give you better insight.

To solve your immediate problem,

Instead of executing the shortcode within the content block, you could instead execute it from the PHP code via

do_shortcode("[<<the shortcode>>]")

Then wrap it in a str_replace, to add the src="".. something like -->

 echo  str_replace('<img','<img src=""',do_shortcode("[<<the shortcode>>]"));