The image disappears on mobile because the left flex column(flex : 15%) is allowed to shrink to 0 width in small screens. flexbox on mobile compresses it completely, so the image (100% of 0) becomes invisible.

To prevent shrinking, we can set minimum width :

.fasciasx { flex-shrink: 0 ;}

or

.fasciasx { min-width: 120px; }

this one keeps the image visible on mobile screen.