How to make a flashing image in imgui?

Question

Now I have a image, have given a abstract method of creating texture (Dp2Px converts int to float)

Gluint mImageTexture = CreateTexture(Resource::getInst()->getImageOne());
ImGui::Image((void*)(intptr_t)mImageTexture, ImVec2(Dp2Px(55), Dp2Px(55)), ImVec2(0, 0), ImVec2(1, 1), ImVec4(1, 1, 1, 1));

Now I want to the image to flash like giving an alert, I tried using a counter but image flashing was not noticeable. I can't use sleep() as it would mean the whole program would sleep instead of only the image. So how to go about this one?