Convert a pen signature like a marker or fountain pen using the tools on line

Starting from this old question, How to convert a signature from JPG to vector strokes?, or other similar, without to have installed anything on my notebook, is there the possibility to trasform my signature written with a ballpoint pen and make it as if I use a marker or fountain pen?

Recommended format for exporting edited images in Inkscsape which are used in LaTeX

I am using Inkscape to edit some images, which will later be used in Latex. The format of the imported images is JPEG. The exported format is PNG. I found that the quality of the exported image from Inkscape was not the same as the original image. The quality had reduced. Which format is recommended so that the quality of the exported image is same as the input image? Please suggest keeping in mind that format of the exported image should be compatible with LaTeX.