[documentation] add screenshots to docs (#459)

README.md

@@ -12,6 +12,10 @@ With GoToSocial, you can keep in touch with your friends, post, read, and share
 
 Documentation is at [docs.gotosocial.org](https://docs.gotosocial.org). You can skip straight to the API documentation [here](https://docs.gotosocial.org/en/latest/api/swagger/).
 
+Here's a screenshot of the instance landing page!
+
+![Screenshot of the landing page for the GoToSocial instance goblin.technology. It shows basic information about the instance; number of users and posts etc.](./docs/assets/instancesplash.png)
+
 ## Table of Contents <!-- omit in toc -->
 
 - [What is GoToSocial?](#what-is-gotosocial)
@@ -45,6 +49,8 @@ GoToSocial provides a lightweight, customizable, and safety-focused entryway int
 
 If you've ever used something like Twitter or Tumblr (or even Myspace!) GoToSocial will probably feel familiar to you: You can follow people and have followers, you make posts which people can favourite and reply to and share, and you scroll through posts from people you follow using a timeline. You can write long posts or short posts, or just post images, it's up to you. You can also, of course, block people or otherwise limit interactions that you don't want by posting just to your friends.
 
+![Screenshot of the web view of a profile in GoToSocial, showing header and avatar, bio, and numbers of followers/following.](./docs/assets/profile1.png)
+
 **GoToSocial does NOT use algorithms or collect data about you to suggest content or 'improve your experience'**. The timeline is chronological: whatever you see at the top of your timeline is there because it's *just been posted*, not because it's been selected as interesting (or controversial) based on your personal profile.
 
 GoToSocial is not designed for 'must-follow' influencers with tens of thousands of followers, and it's not designed to be addictive. Your timeline and your experience is shaped by who you follow and how you interact with people, not by metrics of engagement!

docs/index.md

@@ -10,6 +10,10 @@ With GoToSocial, you can keep in touch with your friends, post, read, and share
 
 GoToSocial provides a lightweight, customizable, and safety-focused entryway into the [Fediverse](https://en.wikipedia.org/wiki/Fediverse), and is comparable to (but distinct from) existing projects such as [Mastodon](https://joinmastodon.org/), [Pleroma](https://pleroma.social/), [Friendica](https://friendica.net), and [PixelFed](https://pixelfed.org/).
 
+Here's a screenshot of the instance landing page!
+
+![Screenshot of the landing page for the GoToSocial instance goblin.technology. It shows basic information about the instance; number of users and posts etc.](./assets/instancesplash.png)
+
 If you've ever used something like Twitter or Tumblr (or even Myspace!) GoToSocial will probably feel familiar to you: You can follow people and have followers, you make posts which people can favourite and reply to and share, and you scroll through posts from people you follow using a timeline. You can write long posts or short posts, or just post images, it's up to you. You can also, of course, block people or otherwise limit interactions that you don't want by posting just to your friends.
 
 **GoToSocial does NOT use algorithms or collect data about you to suggest content or 'improve your experience'**. The timeline is chronological: whatever you see at the top of your timeline is there because it's *just been posted*, not because it's been selected as interesting (or controversial) based on your personal profile.
@@ -18,6 +22,8 @@ GoToSocial is not designed for 'must-follow' influencers with tens of thousands
 
 GoToSocial doesn't claim to be *better* than any other application, but it offers something that might better *for you* in particular.
 
+![Screenshot of the web view of a profile in GoToSocial, showing header and avatar, bio, and numbers of followers/following.](./assets/profile1.png)
+
 ## History and Status
 
 This project sprang up in 2021 out of a dissatisfaction with the safety + privacy features of other Federated microblogging/social media applications, and a desire to implement something a little different.