Image with "filter" on hover

Hello, again it's working fine but i had hard time on the "filter" feature on the ethereum image. So i have put an <a> in a div : the div have the background image of ethereum, and the <a> have the eye with rgba on background color for the effect. I don't know if it's the good method to doing that. I have looked for multi background, mask-image, a with after. But no ones match that i want.

If you have the tips i'm interrested.

Best regards