diff --git a/src/index.js b/src/index.js
index 6f184c3..6ffa502 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,8 +1,53 @@
 import weightedRandom from './weighted-random';
 import svg2png from 'svg2png';
 
+const defaultBlockSize = 36;
+
+const getSizesFromOptOrDefault = opt => {
+  if (opt) {
+    const unparsedSizes = Array.isArray(opt) ? opt : [opt];
+    return unparsedSizes.map(unparsedSize => {
+      const results = /(\d+)x(\d+)/.exec(unparsedSize)
+      if (results) {
+        const w = parseInt(results[1], 10);
+        const h = parseInt(results[2], 10);
+        const s = w / Math.round(w / defaultBlockSize);
+        return {
+          w: w,
+          h: h,
+          s: s,
+        };
+      }
+      else {
+        throw new Error(`Malformed resolution argument: ${unparsedSize}`);
+      }
+    });
+  }
+  else {
+    return [
+      {
+        w: 2880,
+        h: 1800,
+        s: defaultBlockSize,
+      },
+      {
+        w: 750,
+        h: 1334,
+        s: defaultBlockSize,
+      }
+    ];
+  }
+};
+
 export const render = (colors, options) => {
 
+  try {
+    var sizes = getSizesFromOptOrDefault(options['themer-wallpaper-block-wave-size']);
+  }
+  catch(e) {
+    return [Promise.reject(e.message)];
+  }
+
   const colorWeights = new Map([
     ['accent0', 1],
     ['accent1', 1],
@@ -24,14 +69,6 @@ export const render = (colors, options) => {
 
   const colorSets = [{ name: 'dark', colors: colors.dark }, { name: 'light', colors: colors.light }].filter(colorSet => !!colorSet.colors);
 
-  const sizes = [ // TODO: get from args with this and a device being the default
-    {
-      w: 2880,
-      h: 1800,
-      s: 36,
-    },
-  ];
-
   const deepFlatten = arr => arr.reduce((cumulative, inner) => cumulative.concat(Array.isArray(inner) ? deepFlatten(inner) : inner), []);
 
   return deepFlatten(colorSets.map(colorSet => sizes.map(size => {