@MeesterGijs,
The header logo is visible there. So you have to change the header logo
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But, if you don't want to change the header logo and want to use another logo there then paste the below CSS code in wp-admin > WPLMS > Miscellaneous > Custom CSS for WP Login Screen
.login-action-lostpassword div#login h1 a {
background-image: url(imagepath) !important;
}
add the image URL in the above css
@MeesterGijs,
It is working fine. You are trying to add a big image which is cropped due to size. That's why it is showing a blank white image which is actually a cropped image.
refer this: http://prntscr.com/l2fdue