In posts on my feed pictures usually match the topic in some way but not always. The image is used to draw attention and interest so it doesn't always have to match the text. Although, if I ask for a post about tools in your own workshop I expect images of those tools, you know?
So, use a picture that's yours, draw attention to your post and write well, that's all I ask.
I prefer to see people use their own images because it shows character and personality. Also, you only need one image, not ninety seven like some people use, especially if that image is a stock photo.
I think I got this right homie! If not, well, there will be more weeks and I'll try to be there too!