allow doubled avatar resolution

up to now, avatars were restricted to 20k, 256x256 pixel.
resulting in often poor avatar quality.
(the limitation comes from times
where unencrypted outlook inner headers were a thing;
this has changed meanwhile)

to increase quality while keeping a reasonable small size,
for "balanced quality",
we increase the allowed width to 512x512 and the allowed size to 60k.

for "worse quality", things stay unchanged at 128x128 pixel and 20k.

src/blob.rs

@@ -252,24 +252,27 @@ impl<'a> BlobObject<'a> {
     }
 
     pub async fn recode_to_avatar_size(&mut self, context: &Context) -> Result<()> {
-        let img_wh =
+        let (img_wh, max_bytes) =
             match MediaQuality::from_i32(context.get_config_int(Config::MediaQuality).await?)
                 .unwrap_or_default()
             {
-                MediaQuality::Balanced => constants::BALANCED_AVATAR_SIZE,
-                MediaQuality::Worse => constants::WORSE_AVATAR_SIZE,
+                MediaQuality::Balanced => (
+                    constants::BALANCED_AVATAR_SIZE,
+                    constants::BALANCED_AVATAR_BYTES,
+                ),
+                MediaQuality::Worse => {
+                    (constants::WORSE_AVATAR_SIZE, constants::WORSE_AVATAR_BYTES)
+                }
             };
 
         let maybe_sticker = &mut false;
         let strict_limits = true;
-        // max_bytes is 20_000 bytes: Outlook servers don't allow headers larger than 32k.
-        // 32 / 4 * 3 = 24k if you account for base64 encoding. To be safe, we reduced this to 20k.
         self.recode_to_size(
             context,
             None, // The name of an avatar doesn't matter
             maybe_sticker,
             img_wh,
-            20_000,
+            max_bytes,
             strict_limits,
         )?;
 

src/blob/blob_tests.rs

@@ -174,7 +174,7 @@ async fn test_selfavatar_outside_blobdir() {
     let avatar_blob = t.get_config(Config::Selfavatar).await.unwrap().unwrap();
     let avatar_path = Path::new(&avatar_blob);
     assert!(
-        avatar_blob.ends_with("d98cd30ed8f2129bf3968420208849d.jpg"),
+        avatar_blob.ends_with("009161310a6afc319163e4bcabd23b9.jpg"),
         "The avatar filename should be its hash, put instead it's {avatar_blob}"
     );
     let scaled_avatar_size = file_size(avatar_path).await;
@@ -226,7 +226,7 @@ async fn test_selfavatar_in_blobdir() {
         .unwrap();
     let avatar_cfg = t.get_config(Config::Selfavatar).await.unwrap().unwrap();
     assert!(
-        avatar_cfg.ends_with("fa7418e646301203538041f60d03190.png"),
+        avatar_cfg.ends_with("ec054c444a5755adf2b0aaea40209f2.png"),
         "Avatar file name {avatar_cfg} should end with its hash"
     );
 

src/constants.rs

@@ -204,9 +204,11 @@ pub(crate) const DC_FETCH_EXISTING_MSGS_COUNT: i64 = 100;
 pub const BALANCED_IMAGE_BYTES: usize = 500_000;
 pub const WORSE_IMAGE_BYTES: usize = 130_000;
 
-// max. width/height of an avatar
-pub(crate) const BALANCED_AVATAR_SIZE: u32 = 256;
+// max. width/height and bytes of an avatar
+pub(crate) const BALANCED_AVATAR_SIZE: u32 = 512;
+pub(crate) const BALANCED_AVATAR_BYTES: usize = 60_000;
 pub(crate) const WORSE_AVATAR_SIZE: u32 = 128;
+pub(crate) const WORSE_AVATAR_BYTES: usize = 20_000; // this also fits to Outlook servers don't allowing headers larger than 32k.
 
 // max. width/height of images scaled down because of being too huge
 pub const BALANCED_IMAGE_SIZE: u32 = 1280;