Apply max pixel count to blurhashes as well

pipelines/_steps/upload/blurhash_async.go

@@ -8,6 +8,7 @@ import (
 	"github.com/disintegration/imaging"
 	"github.com/turt2live/matrix-media-repo/common/rcontext"
 	"github.com/turt2live/matrix-media-repo/database"
+	"github.com/turt2live/matrix-media-repo/util/readers"
 )
 
 func CalculateBlurhashAsync(ctx rcontext.RequestContext, reader io.Reader, sizeBytes int64, sha256hash string) chan struct{} {
@@ -21,10 +22,24 @@ func CalculateBlurhashAsync(ctx rcontext.RequestContext, reader io.Reader, sizeB
 		if !ctx.Config.Features.MSC2448Blurhash.Enabled {
 			return
 		}
+
+		// Don't blurhash anything we wouldn't thumbnail
 		if ctx.Config.Thumbnails.MaxSourceBytes <= sizeBytes {
 			return
 		}
 
+		// Same goes for pixel size
+		var c image.Config
+		br := readers.NewBufferReadsReader(reader)
+		c, _, err = image.DecodeConfig(br)
+		if err != nil {
+			return
+		}
+		if (c.Width * c.Height) >= ctx.Config.Thumbnails.MaxPixels {
+			return
+		}
+		reader = br.GetRewoundReader()
+
 		var img image.Image
 		img, err = imaging.Decode(reader)
 		if err != nil {