resize range per post

[jhoancito 0]

hello I want to change the size of the image that comes out gray with one hand

 

 

And the other problem is that I want to change the background profile that comes out red and blue for a gif image, I have the code, I don't know where it is.

.pec[data-group_id="4"] {
}
aside.pec[data-group_id="4"] {
background: url("/Image/giphy.gif") repeat 50% 50%; 
background-repeat: no-repeat;
background-size: cover;
}

aside.pec[data-group_id="4"] {
background: #ff0000 !important;
background: -moz-linear-gradient(top, #ff0000 0%, #18138e 92%) !important;
background: -webkit-linear-gradient(top, #ff0000 0%,#18138e 92%) !important;
background: linear-gradient(to bottom, #ff0000 0%,#18138e 92%) !important; 
}