ACPanel > Display > CSs stylesheet paste code vào theo đúng phiên bản diễn đàn của bạn:

PhpBB2:

Code:

.poster-profile img{
      margin-left: 3px;
    border: 5px solid #eee;
    -webkit-box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    -moz-box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    -webkit-transition: all 0.5s ease-out;
    -moz-transition: all 0.5s ease;
    -o-transition: all 0.5s ease;
}
 
.poster-profile img:hover {
    -webkit-transform: rotate(-7deg);
    -moz-transform: rotate(-7deg);
    -o-transform: rotate(-7deg);
}

PhpBB3:

Code:

div.postprofile dl dt img{
      margin-left: 3px;
    border: 5px solid #eee;
    -webkit-box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    -moz-box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    -webkit-transition: all 0.5s ease-out;
    -moz-transition: all 0.5s ease;
    -o-transition: all 0.5s ease;
}
 
div.postprofile dl dt img:hover {
    -webkit-transform: rotate(-7deg);
    -moz-transform: rotate(-7deg);
    -o-transform: rotate(-7deg);
}

PunBB:

Code:

div.user-basic-info img{
    margin: 3px;
    border: 5px solid #eee;
    -webkit-box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    -moz-box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    -webkit-transition: all 0.5s ease-out;
    -moz-transition: all 0.5s ease;
    -o-transition: all 0.5s ease;
}
 
div.user-basic-info img:hover {
    -webkit-transform: rotate(-7deg);
    -moz-transform: rotate(-7deg);
    -o-transform: rotate(-7deg);
}

Invision:

Code:

dl.postdetails dt img{
      margin-bottom: 10px;
    border: 5px solid #eee;
    -webkit-box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    -moz-box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    box-shadow: 4px 4px 4px rgba(0,0,0,0.2);
    -webkit-transition: all 0.5s ease-out;
    -moz-transition: all 0.5s ease;
    -o-transition: all 0.5s ease;
}
 
dl.postdetails dt img:hover {
    -webkit-transform: rotate(-7deg);
    -moz-transform: rotate(-7deg);
    -o-transform: rotate(-7deg);
}

(fmcodes)

demo: