Every image is available for unlocking using gameplay. Since you have never shown a screenshot what you're missing, I can't tell you why you're missing them --- but I have a few ideas:
In v0.89.8
1) There are a couple of scenes based upon whether Becca is shaved or not on which CG you'll get. All you had to do was go replay that scene with the other variable.
2) There are a couple of scenes that are alternate positions for Gerda in the MC's bed. Same thing, call her back to the bedroom and do the other positions.
3) If you don't want to have Danny as Vivian scenes, then your choice not to see them means they won't be in the gallery.
4) There are a couple of optional scenes that lead either into a poorly done intro to netorare or is a netorase scene in the VIP Club bathroom with the bimbo from diner. If you chose not to take those quick peeks, they won't be in the gallery.
If you use the developer-provided save/cheat codes for v0.89.8, all of the above unlocks for content up to v0.82.4/v0.85.1. Any Danny/Vivian content new in v0.89.8 and the scene with the bimbo from the diner can be unlocked during game play.
In v1.07.3, the main route and the netorare (ntr) route are completely separate and if you don't play the route, you won't see the CG gallery.
Those are the ones off the top of my head.
Now, if you really want to know what scenes you're missing - share a screenshot of the gallery showing what is missing. We can help you a lot more that way.
If you use the gallery unlocker, you're trusting the work of some rando off F95 to edit your windows registry using that unlocker. If something goes wrong and it bricks your computer (it hasn't happened yet) you can't hold them responsible because there is no system in place to do so.
Most likely your computer is not up to date on its drivers or is an older OS.
Original is 4k. Here it is in 720p.
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