wpcocktail

<p>The Site Title Caption Modifier is a simple WordPress plugin that sets the caption of all images in your WordPress site to the site title. This is particularly useful for maintaining a consistent branding or style across all posts and pages. The plugin works by hooking into the WordPress ‘img_caption_shortcode’ filter and modifying the caption output.</p>


Image Caption for WP

Automatically sets the caption of all images to your site's title.

dandomains

<p>Customise (or remove) the margin WordPress automatically applies to captions.</p>


Caption Fixer

Customise (or remove) the margin WordPress automatically applies to captions.

Image Caption for WP vs Caption Fixer