As I am drawing using the Pen tool, Curvature tool, or the Pencil - the lines aren't showing even though stroke settings have a colour selected and are appropriate.
Maybe a silly question, but are you sure that the new is in front rather than beneath the coat and other filled things?
And what Ton said.
Unknown to most, it is quite easy to directly show images in posts, hence the following general suggestion:
Please show images by using the Insert Photos button (looks like moon over mountains) for each at the top of the reply box which makes everything appear right there in your post together with your text, rather than the more conspicuous Drag&drop attachment which requires helpers to open a new tab for each image and wait for its showing, then go back and forth; and if they just click it and wait for its showing and press the X to get back to the text, the image is gone so they have to open it again and wait to see it again.