This is probably a bad idea.

config.default.json

@@ -279,6 +279,24 @@
 					"size": 128
 				}
 			}
-		}]
-	}
+		}],
+    "shoot": {
+      "src": "./resources/BulletHole.png",
+      "z": 2,
+      "anchor": {
+        "x": {
+          "absolute": true,
+          "position": 0,
+          "offset": "Math.random()*imgWidth",
+          "size": "123*5"
+        },
+        "y": {
+          "absolute": true,
+          "position": 0,
+          "offset": "Math.random()*imgHeight",
+          "size": "130*5"
+        }
+      }
+    }
+  }
 }

index.js

@@ -34,9 +34,17 @@ _.each(templates, (template, templateName) => {
 // size = width or height of the template/image
 // anchor = the corresponding anchor config
 function calculatePosition(scale, anchor, imageSize) {
+  if (anchor.absolute) {
+    return anchor.offset;
+  }
   return imageSize * anchor.position / 100 - anchor.offset * scale;
 }
 
+function getNumericAnchor(anchor, imgWidth, imgHeight) { // eslint-disable-line no-unused-vars
+  return _.mapValues(anchor, dimension =>
+    _.mapValues(dimension, value => (Number.isFinite(value) ? Number(value) : eval(value)))); // eslint-disable-line no-eval
+}
+
 function render(template, img, size, flipH) {
   let imgWidth = img.width;
   let imgHeight = img.height;
@@ -49,13 +57,21 @@ function render(template, img, size, flipH) {
     if (!size.height) imgHeight = imgHeight * size.width / img.width;
   }
 
-  const xScale = imgWidth / template.anchor.x.size;
-  const yScale = imgHeight / template.anchor.y.size;
+  const anchor = getNumericAnchor(template.anchor, imgWidth, imgHeight);
+  console.log('Numeric anchor: ', anchor);
+  const xScale = imgWidth / anchor.x.size;
+  const yScale = imgHeight / anchor.y.size;
   const templateScale = Math.max(0, Math.min(10, Math.max(xScale || 0, yScale || 0)));
 
+  let templateOffsetX;
+  let templateOffsetY;
+  templateOffsetX = calculatePosition(templateScale, anchor.x, imgWidth);
+  templateOffsetY = calculatePosition(templateScale, anchor.y, imgHeight);
 
-  let templateOffsetX = calculatePosition(templateScale, template.anchor.x, imgWidth);
-  let templateOffsetY = calculatePosition(templateScale, template.anchor.y, imgHeight);
+  console.log('xScale', xScale);
+  console.log('yScale', yScale);
+  console.log('templateOffsetX', templateOffsetX);
+  console.log('templateOffsetY', templateOffsetY);
 
   let imageOffsetX = 0;
   let imageOffsetY = 0;