For whatever it's worth –
I took the html file at qanon.pub and filtered for filenames with jpg/jpeg/png/gif extensions, with the filename having 19 or 41 characters (the lengths of the two fixed-sequence strings), and excluded about a dozen hits where the filename started with things like "screen shot" or other human-created terms.
Then I counted the number of occurrences of all two-character sequences.
If I wrote the parsing software correctly (can't vouch for accuracy) here are the top results:
91 - AA
75 - -4
45 - 4A
44 - AE
34 - -8
29 - -A
26 - 8-
25 - A-
22 - 0A
21 - B-
21 - -9
20 - 6-
20 - 4-
19 - D-
19 - 54
19 - 45
18 - 5-
18 - 41
18 - 2-
17 - -B
17 - 7-
16 - EA
16 - 49
AA does stand out.