There is this weird issue happening where image exports appear to be inserting a border around the image instead of exporting it at the exact size. JPEGs are inserting a white 1px border and PNGs are inserting a 1px transparent border. This issue was already raised in Spectrum last year but there doesn’t appear to be a solution. One response was that perhaps the images are being exported at half pixels but they aren’t, they are exact. You can even see the inserted border in the image preview. https://spectrum.chat/figma/general/white-borders-after-export-image-in-figma~74085064-6f7c-409e-ac37-0f11e4e9ad4e
I’m having the same issue here. Even if my images go over the edge there is a white border. But not on all sides.
I found a temporary solution. If I export the object as a frame, there is no border exported, the image exports to the exact dimensions of the frame. Hope this helps in the interim while they figure out a permanent fix.
I solved it by turning on pixel grid and making sure what edges are snapped to pixel grid. And then export it using File → Export that lets you check if object is at integer coordinates and it is scaled correctly. Sometimes it looses one pixel after scaling.