MDPI is a publisher that allows you to publish in a very short time. Specifically, I suggest considering the journals 'Mathematics,' 'Applied Sciences,' and 'Journal of Imaging.' These publications are notable for their quick turnaround times. Personally, I have had the opportunity to publish in all three and have also served as a reviewer for articles in the first two journals, all of which have been positive experiences.
If you are interested in publishing in 'Mathematics' and 'Applied Sciences,' I would recommend exploring special issues related to imaging.