Use of Wikipedia images I created myself

I think the problem here is that you (a) don't feel like you should be citing the source of this, since you made it yourself but (b) think this will be viewed as plagiarism from Wiki (or, at least, laziness). It seems to me the best way to resolve this is to cite your source, and cite it as yourself via Wikipedia. A short note like (Wikipedia, Original Artist Jane Doe) makes it clear that yes, this is the image from the Wiki page but also that you made it.

When using images from Wikimedia Commons (where they are usually actually hosted) you have to consider two aspects: (i) the license, (ii) scientific citation rules.

(i) is not an issue if you are the creator of the image and it is an original work (and not a derivative of another work). You have not granted rights to Wikipedia for exclusive use of your work (as you would to a journal). Therefore, you don't need permission to use your own images. In practice, you'd need to be able to prove that you are the creator, but if you still have the log-in of the user account that's not a problem. It's even easier if you have released the images into the public domain. If your image is derivative work, the license of the original work(s) applies.

Since you have published the images on Wikimedia Commons and apparently have added them to a Wikipedia article, I would interpret (ii) as requiring self-citation in the same way as if you had used the images in a previous scientific publication of yours.

Obviously, this means that you can't keep the anonymity of your Wikimedia user account, but that doesn't seem to be a concern for you. If it was a concern, you would need to cite it as someone else's work and also follow the requirements of the license.

Thus, I would cite the source like this (adjust to your style):

Image contributed to Wikimedia Commons by me using the pseudonym "Jannick". First used in Wikipedia article "Very important topic" (2015).

Finally let me say that I consider contribution to a free encyclopedia such as Wikipedia a laudable effort. If I saw something like this in a talk or on a poster, I would regard it favorably. However, there are possibly people that consider contribution to Wikipedia wasted effort that would be spent better on writing scientific publications. Decide for yourself if you care about their opinion (I don't).

"Image: Author." or similar.

So long as the license granted to Wikipedia is a nonexclusive one (and I would be very surprised if that isn't the case) there's no need to bring them into it at all. Just show the image, attributed to yourself.