for a long time the header title image was available on the website. Today, the image dissapeared, but is still visible on the other pages. I tried to add image again but no effect. I get the message
Invalid homepage header title image format or upload failed. Accepted formats are .gif, .jpg, or .png.
It is surprising because the image is very small and in png format.
Furthermore, I have problem when I try to add the image to the abstract view. The image was uploaded but is not visible in the abstract. How can fix it? Many thanks in advance for your help.