diff --git a/panel.go b/panel.go
index 6bb726f..e003de2 100644
--- a/panel.go
+++ b/panel.go
@@ -54,7 +54,6 @@ type Labeler interface {
 
 func NewImage(src string, face font.Face, noWindowAccessBar bool) *Panel {
 	ml := MaxLine(src)
-	ml = strings.ReplaceAll(ml, "\t", "    ") // replace tab to whitespace
 	ml = ml + " "
 
 	width := CalcWidth(font.MeasureString(face, " ").Ceil() * len(ml))
diff --git a/util.go b/util.go
index b029f93..20b9971 100644
--- a/util.go
+++ b/util.go
@@ -30,6 +30,8 @@ func ReadString(r io.Reader, face font.Face) (string, error) {
 }
 
 func MaxLine(s string) string {
+	s = strings.ReplaceAll(s, "\t", "    ") // replace tab to whitespace
+
 	var ret string
 	for _, line := range strings.Split(s, "\n") {
 		if utf8.RuneCountInString(ret) < utf8.RuneCountInString(line) {