LuNaTiC

I have added an mp4/gif file in my previous post that demonstrated what I wanted to do in paint.net but for some reason it is not viewable, edited that post. Anyway you guys already got what I wanted @BoltBait yes it does the job thanks. @AndrewDavid that method isn't useful for me since I would draw the rectangle by myself manually which could lead eliminating the pixels I wanted to keep, thank you anyways.

200x200 was just a supposing, what I want in other words is to minimize the image by focusing the center, cropping outer transparent space automatically. Here is an example which can be done in gimp, transforms 800x800 image into 143x577 (577x577 for 1:1 aspect ratio). You may tell me to use gimp then but I usally use paint.net in my editings so it would be cool to have this feature in paint.net, too. https://thumbs.gfycat.com/FairFlawlessChupacabra-mobile.mp4

I guess that's because the image host site does not cover transparency but instead it shows transparency as white background, as this page's background is white too it might have beeen hard to understand. Anyway what I want from paint.net is cropping the image and resize it to either maximum X or Y axis of the original element, for example let's suppose that tube's original Y size is 200 , X size is 50 excluding the outer transparency space and the whole image is 400x400, in this case I want paint.net to automatically resize the image to 200x200 so the original tube elemt won't be cropped but only the outer transparency space would be cropped. Trimming feauture kind of does this but I have to select "magic wand" tool and make some arrangements then every time. So I'm looking for a way to do this process with few clicks, is there plugin you know for that?

Ok I know this maybe very silly question and already supported by the app itself but currently I cannot figure out how to crop outer transparent space of an image automatically which scales up the original image without losing the quality. I know I can achieve this by messing around with tools but I'm looking for a way to automatically do this. If I remember correctly the feautre I'm looking for was avaiable in Gimp. Here's the detailed explanation of what I want to be done automatically by paint.net: