From 80ea90c880e805814d6689769c4a1969f592f539 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Bj=C3=B8rn=20Erik=20Pedersen?=
 <bjorn.erik.pedersen@gmail.com>
Date: Sat, 20 Dec 2025 11:57:34 +0100
Subject: [PATCH] images: Add some more PNG tests

To try to figure out #14288.
---
 tpl/images/images_integration_test.go | 23 +++++++++++++++++++++++
 tpl/images/images_test.go             | 27 ++++++++++++++++++---------
 2 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/tpl/images/images_integration_test.go b/tpl/images/images_integration_test.go
index 59cdd0f46..c6226f611 100644
--- a/tpl/images/images_integration_test.go
+++ b/tpl/images/images_integration_test.go
@@ -142,3 +142,26 @@ Home.
 
 	imagetesting.RunGolden(opts)
 }
+
+func TestPNGIssue14288(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- assets/qr.png --
+sourcefilename: testdata/images_golden/funcs/qr-level-high_scale-6.png
+-- layouts/home.html --
+{{ $img := resources.Get "qr.png" }}
+images.Config: {{ (images.Config "assets/qr.png").Width }}
+Resize to 100x100: {{ ($img.Resize "100x100" ).Width }}
+Brightnes method: {{ ($img.Filter (images.Brightness 12) ).RelPermalink }}
+Brightnes func: {{ ($img | images.Filter (images.Brightness 12) ).RelPermalink }}
+`
+
+	b := hugolib.Test(t, files)
+	b.AssertFileContent("public/index.html", `
+images.Config: 222
+Resize to 100x100: 100
+Brightnes method: /qr_hu_d5f06fd7594d0594.png
+Brightnes func: /qr_hu_d5f06fd7594d0594.png
+`)
+}
diff --git a/tpl/images/images_test.go b/tpl/images/images_test.go
index 4f656d1f9..be5db69fe 100644
--- a/tpl/images/images_test.go
+++ b/tpl/images/images_test.go
@@ -17,27 +17,32 @@ import (
 	"bytes"
 	"image"
 	"image/color"
-	"image/png"
 	"path/filepath"
 	"testing"
 
 	qt "github.com/frankban/quicktest"
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/config/testconfig"
+	"github.com/gohugoio/hugo/resources/images"
 	"github.com/spf13/afero"
 	"github.com/spf13/cast"
 )
 
 type tstNoStringer struct{}
 
+type widthHeight struct {
+	Width  int
+	Height int
+}
+
 var configTests = []struct {
 	path   any
-	input  []byte
+	input  widthHeight
 	expect any
 }{
 	{
 		path:  "a.png",
-		input: blankImage(10, 10),
+		input: widthHeight{10, 10},
 		expect: image.Config{
 			Width:      10,
 			Height:     10,
@@ -46,7 +51,7 @@ var configTests = []struct {
 	},
 	{
 		path:  "a.png",
-		input: blankImage(10, 10),
+		input: widthHeight{10, 10},
 		expect: image.Config{
 			Width:      10,
 			Height:     10,
@@ -55,7 +60,7 @@ var configTests = []struct {
 	},
 	{
 		path:  "b.png",
-		input: blankImage(20, 15),
+		input: widthHeight{20, 15},
 		expect: image.Config{
 			Width:      20,
 			Height:     15,
@@ -64,7 +69,7 @@ var configTests = []struct {
 	},
 	{
 		path:  "a.png",
-		input: blankImage(20, 15),
+		input: widthHeight{20, 15},
 		expect: image.Config{
 			Width:      10,
 			Height:     10,
@@ -101,7 +106,8 @@ func TestNSConfig(t *testing.T) {
 		// cast path to string for afero.WriteFile
 		sp, err := cast.ToStringE(test.path)
 		c.Assert(err, qt.IsNil)
-		afero.WriteFile(ns.deps.Fs.Source, filepath.Join(bcfg.WorkingDir(), sp), test.input, 0o755)
+		img := blankImage(d.ResourceSpec.Imaging.Codec, test.input.Width, test.input.Height)
+		afero.WriteFile(ns.deps.Fs.Source, filepath.Join(bcfg.WorkingDir(), sp), img, 0o755)
 
 		result, err := ns.Config(test.path)
 
@@ -111,10 +117,13 @@ func TestNSConfig(t *testing.T) {
 	}
 }
 
-func blankImage(width, height int) []byte {
+func blankImage(codec *images.Codec, width, height int) []byte {
 	var buf bytes.Buffer
 	img := image.NewRGBA(image.Rect(0, 0, width, height))
-	if err := png.Encode(&buf, img); err != nil {
+	cfg := images.ImageConfig{
+		TargetFormat: images.PNG,
+	}
+	if err := codec.EncodeTo(cfg, &buf, img); err != nil {
 		panic(err)
 	}
 	return buf.Bytes()
-- 
2.39.5