The file names for the images that comprise the body of each e-mail message appear to be random numbers, but are in fact written in "leet-speak" with names appropriate to the subject of the e-mail (for example, the first image in the "fratricide" e-mail is named "fr4_7ri_cid3_01.jpg").
Confirmed image files associated with unfound e-mails:
sickle - 5ick13_01.jpg, 5ick13_02.jpg, 5ick13_03.jpg
spore - 5p0r3_01.jpg, 5p0r3_02.jpg, 5p0r3_03.jpg
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