1st picture seems to be pixels of slightly different colors.
For the 2nd picture, I filled the picture with black in paint, this might be useful.
For the 3rd picture, the watermark says www.iconexperience.com.
Independently of @Randal'Thor's answer (which was posted in its original form just a few minutes before this one), I have explanations for all 16 puzzles (15 solid, 1 less so), and must say from the off:
The puzzles resolve as follows (I am least sure on #6):
Altogether, these spell out:
Do possessive nouns count? Also, is there a specific dictionary that the word has to be in? For S, the word "suss's" (4/5) would beat out "assess" and "sasses." If possessive nouns aren't allowed, then "susses" would tie for the record (4/6).
I think the answer may be
This might fit with the first Penta-decker Vowelburger, since
A pedantic note:
Feedback section: this one was relatively quick and easy to solve, mostly because of the final clue. The number 26 is naturally going to bring one thing to mind, and (assuming we're OK with the pedantic note above) ...
The answer is
Feedback section: the method of solution wasn't very clear until after the hints. At first I'd assumed we'd be looking for three-letter words each time, so I didn't get anywhere solving this. It was clear that part of the puzzle would be to figure out why there's a number together with each ...
According to Qat, here are the longest words with a single vowel:
giving a score of
These words are all in M-W; this is likely optimal. (Because of English syllable restrictions, it is very unlikely that including two vowels in the same word will increase the total number of letters you can get.)