Hello @Joppe welcome to the Local Guides Connect community!!
According to your profile, only 3 of the 351 photos you posted are hidden (compare the numbers marked in green on my screenshot):
One reason for not publishing, could be too many duplicate or redundant photos, like those, I saw immediately and marked them in red on my screenshot.
Another reason could be, if photos are attached to a review, the complete review including all attached photos will be hidden, if the text or only a single photo is found suspicious for SPAM or violating the rules. As I can see, you posted 76 reviews and rated 54 times without text, but only 71 are published. This might be an indication, your real problem is not related to photos but to your reviews.
I suggest this article How to Get In and Out of Trouble: The Main post by @MortenCopenhagen with many hints what could be done and should be avoided to reduce the number of hidden photos or reviews.