WordPress.org

The most popular WordPress gallery plugin and one of the most popular plugins of all time with over 16 million downloads.

By: photocrati and imagely.

Supercharge your WordPress theme with mega pack of shortcodes

By: MadFork and Vladimir Anokhin.

Reduce image file sizes, improve performance and boost your SEO using the free WPMU DEV WordPress Smush API.

By: WPMU DEV - Your WordPress Team and Alex Dunae.

Share buttons for WordPress including the AddToAny sharing button, Facebook, Twitter, Google+, Pinterest, WhatsApp, many more, and follow icons too.

By: micropat and addtoany.

Photo Gallery is an advanced plugin with a list of tools and options for adding and editing images for different views. It is fully responsive.

By: webdorado.

Responsive Lightbox allows users to view larger versions of images and galleries in a lightbox (overlay) effect optimized for mobile devices.

By: dFactory.

SEO Friendly Images automatically adds alt and title attributes to all your images improving traffic from search engines.

By: Vladimir Prelovac.

Easily add a Favicon to your site and the WordPress admin pages. Complete with upload functionality. Supports all three Favicon types (ico,png,gif).

By: techotronic.

Automatically publishes blogposts to profiles/pages/groups on Facebook, Twitter, Instagram, Google+, Pinterest, LinkedIn, Blogger, Tumblr ... 22 more

By: NextScripts.

The highly customizable lightbox for WordPress

By: Archetyped.

Imsanity automatically resizes huge image uploads. Are contributors uploading huge photos? Tired of manually scaling? Imsanity to the rescue!

By: Jason.

Take complete control over the WordPress content editor.

By: Josh.

Automatically generate the Post Thumbnail (Featured Thumbnail) from the first image in post or any custom post type only if Post Thumbnail is not set

By: tariquesani.

Integrate a fancy slideshow in just five steps. - Rainbows. Rainbows everywhere.

By: Stefan Boonstra.

Description: Beef up the WordPress TinyMCE content editor with a plethora of advanced options.

By: Josh and Marventus.

Seamlessly integrates FancyBox lightbox into your WordPress blog: Upload, activate, and you're done. Additional configuration optional.

By: Silkalns.

A better management for WordPress Media Library

By: webbistro.

Lazy load images to improve page load times and server bandwidth. Images are loaded only when visible to the user.

By: Mohammad Jangda, Automattic, Jake Goldman, and 10up.

Speed up your website. Optimize your JPEG and PNG images automatically with TinyPNG.

By: TinyPNG.

A responsive image lightbox for WordPress galleries & Foo Gallery

By: bradvin, fooplugins, and Freemius.

The Lightbox Gallery plugin changes the view of galleries to the lightbox.

By: Hiroaki Miyashita.

Very easy to use WordPress lightbox plugin to display YouTube and Vimeo videos in an elegant lightbox overlay.

By: Tips and Tricks HQ, Ruhul Amin, and wptipsntricks.

Instagram Slider Widget is a responsive slider widget that shows 12 latest images from a public instagram user or up to 18 images from a hashtag.

By: jetonr.

Foo Gallery is the most intuitive and extensible gallery management tool ever created for WordPress.

By: bradvin and fooplugins.

An easy-to-use image script for adding things such as thumbnail, slider, gallery, and feature images.

By: Justin Tadlock.

Adds Colorbox/Lightbox functionality to images, grouped by post or page. Works for WordPress and NextGEN galleries. Comes with different themes.

By: techotronic.

Slider WD plugin is a great tool for creating responsive sliders. It uses various transition effects.

By: webdorado.

Custom feeds for Facebook Pages, Groups, Events, Album Photos, Videos & Covers, Twitter, Vine, Instagram, Pinterest & YouTube on pages, posts

By: slickremix.

Lazy loading for images and iframes makes your site load faster and saves bandwidth. Uses no external JS libraries and degrades gracefully for non-js

By: Bjørn Johansen.

Feature content in a JavaScript powered slideshow gallery showcase on your WordPress website

By: Tribulant Software.