Hi, It requires a theme files customization which we do not support. You have to do it yourself or find somebody who'll be able to do it.
Custom CSS won't be useful here, because image still will be as 150px x 75px so, it will get only more pixelated while being resizing it to bigger resolution.
Do not forget about changing theme to Child Theme if you want to make this modication.
Thanx for the info. Just one question though, what do you mean about Child Themes? As far as I am aware there is not Child Theme available. We installed Betheme and activated a pre-built template.
Child Theme is a theme that inherits the functionality and styling from the parent theme. If you don't have a child theme and you modified theme files, when you'll update the theme, all changes will be lost. A child theme is made for saving these modifications while updating the theme.
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It requires a theme files customization which we do not support.
You have to do it yourself or find somebody who'll be able to do it.
Custom CSS won't be useful here, because image still will be as 150px x 75px so, it will get
only more pixelated while being resizing it to bigger resolution.
https://codex.wordpress.org/Child_Themes
Child Theme is a theme that inherits the functionality and styling from the parent theme.
If you don't have a child theme and you modified theme files, when you'll update the theme, all changes will be lost.
A child theme is made for saving these modifications while updating the theme.
Thanks.