refactor(png): add support to convert the png file to a suitable colo…

…r model at the time to convert the image to a pdf format

pkg/files/images/png.go

@@ -3,6 +3,8 @@ package images
 import (
 	"bytes"
 	"fmt"
+	"image"
+	"image/draw"
 	"image/png"
 	"slices"
 	"strings"
@@ -75,7 +77,10 @@ func (p *Png) ConvertTo(fileType, subType string, fileBytes []byte) ([]byte, err
 			return nil, err
 		}
 
-		result, err = convertToDocument(subType, img)
+		rgba := image.NewRGBA(img.Bounds())
+		draw.Draw(rgba, img.Bounds(), img, image.Point{}, draw.Src)
+
+		result, err = convertToDocument(subType, rgba)
 		if err != nil {
 			return nil, fmt.Errorf(
 				"ConvertTo: error at converting image to another format: %w",