I use a image program called (Draw plus) from serif and if you create a image at 50x50 it defaults to 96 dpi
50x50 what if I may ask? Draw plus is a vector program so you can export at whatever size you like.
And what is shown below happens because you do not set a size in pixels, but you have some random size in inches, centimetres or whatever - then DPI behaves like a multiplier, like I said - at 96dpi your image is this many pixels when exported so at 192 it would be twice as many, of course.
But if you set your size in pixels (as you should, since we work in pixels here) then it will be that size in pixels and DPI is still meaningless. When working with vector art a decent approach is to decide a certain unit to be equal to a pixel (I use 1 millimeter) - and then work and export according to that assumption. So you set a canvas of, say, 512x512mm and export by setting a PIXEL size of 512x512px. This way you can be sure that a line 1mm thick will be 1px thick, etc. Which, in turn, means better, more consistent artwork.