The moderators have been on duty for almost a month now, and having rejected a few puzzles, I thought it might be useful to puzzle makers to know what makes a moderator cringe and click on the reject button …
……..— These are not necessarily the opinions of all the moderators

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o Pictures too small (Especially when not all the 500 × 500 (or 400×300 for cryptopix) space is used)
o Pictures blurry
o Requires uncommon knowledge with no clue on how or where to find/research the information
o Relies on identification of people (or comic strip characters, or album covers, or anything “pop culture”) with no clues other than just the photo
o Too much ambiguity
o Solution method is unnecessarily tedious (with no payoff or fun steps along the way)
o Has errors in the solution method or puzzle construction
o Solution method is incomplete or vague (Include ALL the details – and steps please),

edit: (Thanks Steph)
o Requires gratuitous anagramming