Instant Sketch Free is designed to turn any photo you take or have stored in your photo library into a sketched image and it does so quite well. The app looks fairly basic, at first, but the filter runs quickly; and with an HD mode that creates more manga-like images than the standard SD filter, you can go above and beyond what most all-in-one photo filters offer.
The key to Instant Sketch Free is the added functionality that you won't find in regular filtering tools. Most single-function photo editors lack the depth needed to merit a download. But Instant Sketch Free manages to expand on the tools and resources provided for sketch-filtered images in many ways. The interface is fairly standard and not always clearly labeled, so it will take a bit of time to get down; but once you do, there aren't many menus to dig through. You can select an image, choose to convert to SD or HD, and then share it. The HD option supposedly takes longer, but we noticed only a small increase in time taken, and the end result was definitely worth the small wait. When done, you can edit things like brightness and detail, as well. While there were plenty of ways to transform your image, the app was light on options to share your artwork; but we prefer that to having minimal tools and multiple sharing methods.
Instant Sketch Free is a solid, free app for your iPhone that allows you to turn any image you have into a comic-style vignette. It's not perfect, but the filtering works well and the resulting images fit the promise of looking like they were hand drawn.