User pictures in Feedback module appear squeezed to 5px height in the "Show responses" and "Show non-respondents" tabs (mod/feedback/show_entries.php, mod/feedback/show_nonrespondents.php).

This is a side effect of setting mod_feedback analysis bar heights to 5px in "Analysis" tab (mod/feedback/analysis.php), introduced in MDL-42711.

Here's the CSS-definition in theme/bootstrapbase/less/moodle/modules.less:

.path-mod-feedback .generalbox div table tbody img {

    height: 5px; // we should remove the bar height specification in core

}

A more exact definition would help avoid this kind of misinterpretations.
Something like this would work better:

#page-mod-feedback-analysis img.feedback_bar_image {

    height: 5px; // we should remove the bar height specification in core

}

The following lines can probably be removed from mod/feedback/styles.css if they are not required by other themes.

div img.feedback_bar_image {

    height: 10px;

}