When inverted, the numbers form ASCII code, which has been translated (as best as possible) on the wiki into a rambling message that doesn't yet explain the image. Also of note, all of the puzzle pieces' filenames (e..g, "berets or scoop," "bee torso crops," "sorbet coopers" and "sort eco probes") are anagrams of each other. One particularly intriguing combination that's not been used -- "reboot process" -- could be the missing piece, as well as a reference to GLaDOS, which in turn could neatly tie this apparent ARG to marketing for this month's Portal 2. (This puzzle is just one part of an extensive game orchestrated by Valve that began on April Fools' Day -- catch up here.)
Of course, if the image is of a bathysphere (or diving bell), the next logical step leads us to the Borealis, an Aperture Science sea vessel first mentioned in Half-Life 2: Episode Two and speculated to be the subject of a Portal 2 Achievement. Now, if you really want to get your hopes up, you'll recall that the Borealis was also the apparent subject of early Half-Life 2: Episode Three concept art. Deep breath! Okay, now relax.