How to use custom .png-Images instead of mat-icons for a button?

I have implemented two buttons in my Angular application, with which the user can change the displayed language. Now, instead of the two buttons with “German” & “English”, I want to use two icons with the respective country flag. First I tried it with the “Mat-Icons”, unfortunately there are no suitable icons for my use case. Therefore I downloaded two .png files with the respective country flags from Flaticon, saved them in /assets/icons and would now like to integrate these instead of the mat icons. Unfortunately, I just can’t get this to work at all and would therefore appreciate some help – thanks!

How to change color of link and icon when isActive?

I have icon inside Link tag in my React component. I would like when Link is active to change the color of icon also. According to the code written below, when the link is active, the color of the icon also changes. But when I set the color of the icon in its css, the color of the icon no longer changes when the link is active. How would I change that?