Use pngn instead of image/png

cmd/cbconvert-gui/go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/fvbommel/sortorder v1.1.0
 	github.com/gen2brain/cbconvert v1.2.1-0.20260824143641-01a205a07eb9
 	github.com/gen2brain/iup-go/iup v0.32.1-0.20260627135200-7df674d35173
+	github.com/gen2brain/pngn v0.1.2
 )
 
 require (

cmd/cbconvert-gui/go.sum

@@ -48,6 +48,8 @@ github.com/gen2brain/jpegn v0.6.1 h1:S+Em15BvqCl/cTvebB6JU67ndDVdFWPhB0GbxNkWlOE
 github.com/gen2brain/jpegn v0.6.1/go.mod h1:43hks+w5VNTUDU34uk0tsXYJ97nbYL2idAlZF0D66+A=
 github.com/gen2brain/jxl v0.2.0 h1:cXSQnfbcC0JGFzaI344VzPMbe7mh6rYc0tjPcBUsE4U=
 github.com/gen2brain/jxl v0.2.0/go.mod h1:VjJHRai/8I8Es01mULqyiOihRBOjJr1Zo+NoN/MyIwo=
+github.com/gen2brain/pngn v0.1.2 h1:j1ikFmwRpJnVxnFcwekIMYzBLOsEXDVrOSHCwqQcnV8=
+github.com/gen2brain/pngn v0.1.2/go.mod h1:jmw3LV2MHgoK4PBdsLC3YTiLUBaY5Nlfi3UFvxqJc9E=
 github.com/gen2brain/vpx v0.2.1 h1:UD6tibcs/zlaIOKNFXeVyZuHBEaW9GYfxKSxvAN9cc8=
 github.com/gen2brain/vpx v0.2.1/go.mod h1:EVIdqguMSiapbtjDm4AWgFgYYJ4d+k8trXqjxYZ/4XE=
 github.com/go-errors/errors v1.0.1/go.mod h1:f4zRHt4oKfwPJE5k8C9vpYG+aDHdBFUsgrm6/TyX73Q=

cmd/cbconvert-gui/main.go

@@ -5,7 +5,6 @@ import (
 	_ "embed"
 	"flag"
 	"fmt"
-	"image/png"
 	"os"
 	"path/filepath"
 	"runtime/debug"
@@ -14,6 +13,7 @@ import (
 	"github.com/gen2brain/cbconvert"
 	"github.com/gen2brain/cbconvert/cmd/cbconvert-gui/i18n"
 	"github.com/gen2brain/iup-go/iup"
+	"github.com/gen2brain/pngn"
 )
 
 //go:generate rsrc --ico dist/windows/icon.ico --arch amd64 -o main_windows_amd64.syso
@@ -85,7 +85,7 @@ func main() {
 	config = iup.Config()
 	iup.ConfigLoad(config)
 
-	img, _ := png.Decode(bytes.NewReader(appLogo))
+	img, _ := pngn.Decode(bytes.NewReader(appLogo))
 	iup.ImageFromImage(img).SetHandle("logo")
 
 	dlg := iup.Dialog(layout()).SetAttributes(fmt.Sprintf(`TITLE="CBconvert %s", ICON=logo`, appVersion)).SetHandle("dlg")