It is a little unclear what steps you are taking, an at what point the resize happens, and whether it is the playable board that is resizing (ie, the number of squares) or the asset that you would add to the board, or whether you're changing the scale of representation (how much 1 square represents), or number of pixels in a square... If what Gauss has suggested doesn't get you sorted, then I'd suggest using a series of screenshots if you can't upload your video. Just as a point of clarification, in case it matters: you can't "paste" an image (or a video) into a post, here. You have to use the "Image" button (second from the right on the formatting toolbar, then choose the image/video to upload/embed. If your video still won't post this way, it might be too big, in which case you might be able to scale it down with an online tool before posting it, and/or you could post it elsewhere and then link to it, here. Alternatively, a tool like Screen Recorder will automatically upload a video you take to their servers and provide you a link to the file. Not sure how long that link lasts, but it's an easy way to get a screen capture to a place that is widely viewable.