Zoomable digital images

A method, executable by a device, comprising:

• reading, from a file storage configured for storing files of source images in a particular file format, a file representing a source image, the file comprising a first image and a second image, the first image comprising a first plurality of pixels, the second image comprising a second plurality of pixels, each pixel in the first and second images having a same, particular size;
• generating the source image by:
• using the first image as an interior image of the source image, and
• generating a set of successive exterior images that corresponds to a set of successive zoom levels, each zoom level in the set of successive zoom levels successively larger than any prior zoom levels, each exterior image in the set of successive exterior images comprising a plurality of pixels from a portion of the second plurality of pixels of the second image configured to completely encompass the interior image and any prior exterior images, a size of each pixel in the plurality of pixels of each exterior image in the set of successive exterior images larger than the particular size and a size of the plurality of pixels of any prior exterior image, the size of each pixel in the plurality of pixels of each exterior image in the set of successive exterior images based on a factor of the size of a side of the interior image divided by the size of the side of the interior image minus two pixels;
• receiving a selection of a zoom level in the set of successive zoom levels;
• and
• generating a target image based on the selected zoom level and the source image.

A system comprising:

• a set of processing units;
• and
• a non-transitory computer-readable medium storing instructions that when executed by at least one processing unit in the set of processing units cause the at least one processing unit to:
• read, from a file storage configured for storing files of source images in a particular file format, a file representing a source image, the file comprising a first image and a second image, the first image comprising a first plurality of pixels, the second image comprising a second plurality of pixels, each pixel in the interior image having a same, particular size;
• generate the source image by:
• using the first image as an interior image of the source image, and
• generating a set of successive exterior images that corresponds to a set of successive zoom levels, each zoom level in the set of successive zoom levels successively larger than any prior zoom levels, each exterior image in the set of successive exterior images comprising a plurality of pixels from a portion of the second plurality of pixels of the second image configured to completely encompass the interior image and any prior exterior images, a size of each pixel in the plurality of pixels of each exterior image in the set of successive exterior images larger than the particular size and the size of the plurality of pixels of any prior exterior image, the size of each pixel in the plurality of pixels of each exterior image in the set of successive exterior images based on a factor of the size of a side of the interior image divided by the size of the side of the interior image minus two pixels;
• receive a selection of a zoom level in the set of successive zoom levels;
• and
• generate a target image based on the selected zoom level and the source image.