Image forming apparatus, sheet feed control method, and storage medium

An image forming apparatus that selectively feeds recording sheets from a plurality of accommodating units to form an image on each of the recording sheets according to image data, comprising:

• a first size designation unit configured to designate a standard size or a non-standard size for each of respective sizes of recording sheets accommodated in the accommodating units;
• a second size designation unit configured to designate vertical and lateral lengths of recording sheets, for the non-standard size;
• a third size designation unit configured to designate a free size in which vertical and lateral lengths of recording sheets are not designated, for the non-standard size;
• and
• a sheet feed control unit configured to be operable when the image data is associated with the non-standard size, to feed, if there is an accommodating unit accommodating recording sheets of which vertical and lateral lengths corresponding to vertical and lateral lengths represented by the image data are designated, a recording sheet from the accommodating unit, and feed, if there is no accommodating unit accommodating the recording sheets of which the vertical and lateral lengths corresponding to the vertical and lateral lengths represented by the image data are designated, a recording sheet from an accommodating unit accommodating recording sheets of the free size.