Change Effect speed applied to still image

Hello,
I added a still image into timeline and assigned Glitch-Effect to that. Unfortunatelly it's too fast and I want to slow down the effect. But how?

There is neither retime nor clip speed of course because it's a still image. Do you have Idea how to achieve that?

Best regards
Floh

Compound Clip. Adjustment Clip. Nested Timeline.

Play around with those. Report back for others.