restrict file types and add help text about game data

index.pug

@@ -12,7 +12,7 @@ html(lang="en-gb")
                 | pixsy
                 //img(alt="pixsy" src="includes/pixsy.png")
             p.
-                convert images to Bitsy rooms
+                version 0.72.7
                 |
                 #[a(href="http://tinybird.info/image-to-bitsy/old/" target="_blank") old version]
                 |
@@ -21,12 +21,30 @@ html(lang="en-gb")
                 #[a(href="https://twitter.com/synth_ruiner") twitter]
         .pages
             .page#start
+                p.
+                    #[b pixsy] is a tool for #[a(href="http://bitsy.org/") Bitsy Game Maker]
+                    that allows you to generate a room from an image and add it to your game.
+                p this version is compatible with Bitsy version 7.2 and earlier.
+                p.
+                    #[b pixsy] does not currently work via the Itch desktop program.
+                    some users are also currently reporting problems.
+                    if pixsy does not work for you, please try the
+                    #[a(href="http://tinybird.info/image-to-bitsy/old/") old version] instead.
+                p.
+                    instructions can be found on the
+                    #[a(href="https://ruin.itch.io/pixsy/") itch.io page] -
+                    scroll down to "how to use".
+
                 button.normal.pagination.next#new create a new bitsy game
                 button.normal.pagination.next#load load an existing bitsy game
             .page.game-data
                 h2 game data
 
-                input#game(type="file" autocomplete="off")
+                p.
+                    your game data is available from the #[i game data] window in bitsy,
+                    under the #[i tools] dropdown.
+
+                input#game(type="file" accept=".bitsy,.txt" autocomplete="off")
                 br
 
                 textarea#game-data(