[performance] move thumbnail generation to go code where possible (#3183)

* wrap thumbnailing code to handle generation natively where possible

* more code comments!

* add even more code comments!

* add code comments about blurhash generation

* maintain image rotation if contained in exif data

* move rotation before resizing

* ensure pix_fmt actually selected by ffprobe, check for alpha layer with gifs

* use linear instead of nearest-neighbour for resizing

* work with image "orientation" instead of "rotation". use default 75% quality for both webp and jpeg generation

* add header to new file

* use thumb extension when getting thumb mime type

* update test models and tests with new media processing

* add suggested code comments

* add note about thumbnail filter count reducing memory usage

1 files changed, 2 insertions, 2 deletions

diff --git a/internal/api/fileserver/servefile_test.go b/internal/api/fileserver/servefile_test.go
index 9cd1517e2..33afe34d0 100644
--- a/internal/api/fileserver/servefile_test.go
+++ b/internal/api/fileserver/servefile_test.go
@@ -166,7 +166,7 @@ func (suite *ServeFileTestSuite) TestServeSmallRemoteFileOK() {
 	)
 
 	suite.Equal(http.StatusOK, code)
-	suite.Equal("image/webp", headers.Get("content-type"))
+	suite.Equal("image/jpeg", headers.Get("content-type"))
 	suite.Equal(fileInStorage, body)
 }
 
@@ -212,7 +212,7 @@ func (suite *ServeFileTestSuite) TestServeSmallRemoteFileRecache() {
 	)
 
 	suite.Equal(http.StatusOK, code)
-	suite.Equal("image/webp", headers.Get("content-type"))
+	suite.Equal("image/jpeg", headers.Get("content-type"))
 	suite.Equal(fileInStorage, body)
 }