can you attach the image you try to upload here, please?

It is attached to the first post. 

not the screenshot of mobile the image of the logo itself

It's here sauwpc.us. Top left corner. I added it to the mobile site and then tried resizing it but it didn't change. It isn't the exact ratio as the available space. 

Please provide that logo image in the attachment

Here you go. 

Something is wrong on your side. Is this the original image you tried to upload. Because it looks ok on our side?
Can you please try another image? also attach that image here as well.

Garrett all right. mobile logo problematic

great logos, blurring

I did upload a bigger version first. Thought I had replaced it with the smaller one. Should I delete the file manually from the server and start over? It appears replacing it didn't work.

Garrett

have you tried to click on "reset" button next to the mobile logo in the theme customizer and then upload another image?

Yes, and tried it again. 

Is there a maximum size for the logo? It seems to handle the height OK, but not the width. 

The problem is in the image, it is long but not wide enough. You should keep the ratio like 2:3

If you upload this image it will be displayed properly: 

thanks. 

No problem