target dir via t parameter in image_process filter

helper/template_filters.go

@@ -109,6 +109,8 @@ func parseImageParams(str string) (*config.ImagingConfig, error) {
 			p.Height, err = strconv.Atoi(e[1])
 		case "f":
 			p.Filename = e[1]
+		case "t":
+			p.TargetDir = e[1]
 		case "p":
 			p.Process = e[1]
 		case "a":
@@ -207,7 +209,29 @@ func ImageProcessFilter(in *pongo2.Value, param *pongo2.Value) (*pongo2.Value, *
 		}
 	}
 
-	imgTarget := ResolveOutputPath(p.Filename)
+	var imgTarget string
+	if p.TargetDir != "" {
+		imgTarget = ResolveOutputPath(
+			path.Clean(p.TargetDir) + "/" +
+				p.Filename,
+		)
+
+		pt := path.Dir(imgTarget)
+		if _, err := os.Stat(pt); os.IsNotExist(err) {
+			Log.Infof("create image target dir: %s", pt)
+			if err := os.MkdirAll(pt, 0755); err != nil {
+				return nil, &pongo2.Error{
+					Sender:    "filter:image_resize",
+					OrigError: fmt.Errorf("could not create image target dir '%s': %s", pt, err),
+				}
+			}
+		}
+
+		p.Filename = ResolveNavPath(p.TargetDir + "/" + p.Filename)
+
+	} else {
+		imgTarget = ResolveOutputPath(p.Filename)
+	}
 
 	if f, err := os.Stat(imgTarget); err == nil && !f.IsDir() {
 		Log.Noticef("skipped processing image from %s to %s, file already exists", imgSource, imgTarget)