fix: make sure generating blur hashes for bmp, tiff and webp images works

pkg/migration/20211212210054.go

@@ -17,6 +17,7 @@
 package migration
 
 import (
+	"errors"
 	"image"
 
 	"code.vikunja.io/api/pkg/files"
@@ -64,9 +65,12 @@ func init() {
 				}
 
 				src, _, err := image.Decode(bgFile.File)
-				if err != nil {
+				if err != nil && !errors.Is(err, image.ErrFormat) {
 					return err
 				}
+				if err != nil && errors.Is(err, image.ErrFormat) {
+					log.Warningf("Could not generate a blur hash of list %d's background image: %s", l.ID, err)
+				}
 
 				dst := image.NewRGBA(image.Rect(0, 0, 32, 32))
 				draw.NearestNeighbor.Scale(dst, dst.Rect, src, src.Bounds(), draw.Over, nil)

pkg/modules/background/handler/background.go

@@ -17,10 +17,15 @@
 package handler
 
 import (
-	"image"
 	_ "image/gif"  // To make sure the decoder used for generating blurHashes recognizes gifs
 	_ "image/jpeg" // To make sure the decoder used for generating blurHashes recognizes jpgs
 	_ "image/png"  // To make sure the decoder used for generating blurHashes recognizes pngs
+
+	_ "golang.org/x/image/bmp"  // To make sure the decoder used for generating blurHashes recognizes bmps
+	_ "golang.org/x/image/tiff" // To make sure the decoder used for generating blurHashes recognizes tiffs
+	_ "golang.org/x/image/webp" // To make sure the decoder used for generating blurHashes recognizes tiffs
+
+	"image"
 	"io"
 	"net/http"
 	"strconv"