Painnt is an Android application that offers users a large number of filters, allowing them to quickly make changes to pictures. Read more about Painnt  

A quick and easy way to make improvements to an image is by putting it trough a professional filter. Sure, editing the image with a professional application can take a long time and you might now want to wait for so long, not to mention that such app would be an expensive one.
On the other hand, applying a filter is much easier to do, and the result will likely satisfy most of the users that are not really all that pretentious. As you can imagine, all of the filters can be fine-tuned to some degree, which means that people will be able to get different results.