1. A method for rendering text with an image comprising: receiving, by one or more computing devices, a source image; receiving, by the one or more computing devices, a separate block of text to be associated with the source image, wherein the block of text is not included in the source image when received; segmenting, by the one or more computing devices, the block of text into a plurality of text segments, wherein each text segment comprises a sequence of alpha-numeric characters; on each of a plurality of threads running in parallel, generating a text bitmap for a respective text segment from the plurality of text segments, the text bitmap illustrating the sequence of alpha-numeric characters for the respective text segment; and compositing, by the one or more computing devices, each of the text bitmaps with an image bitmap of the source image, wherein the composited image bitmap comprises a rendering of the block of text onto the source image.