So, I have this .svg file, and I want to edit the nodes, the file size is 1.72mb, and I'd like to lower it down to 16kb, it's pretty big. I have another version of it, but all the colors have been turned into stripes and it doesn't look the best.

But, I edit the image via changing the display to outline, and all I get is a white rectangle with a red X, how do I fix it?

I'm pretty new to inkscape, which is why I don't know the basics yet exactly, but I'm learning.

Hi.

The red x indicates a raster image. Judged by the file size, it's embedded into your svg.
You'll need to trace it first to be able to edit it as a vector object. Either redraw it manually or use the trace bitmap option under the path menu.