Twitter Gallery maximize and image right-clickable.

TwitterGalleryImprove.user.css

@-moz-document domain("twitter.com") {
.GalleryNav--prev,
.GalleryNav--next {
    width: 30% !important;
}
.Gallery-content,
.media-image {
    width: auto !important;
    height: auto !important;
}
.Gallery-content {
    max-width: calc(100% - 10px) !important;
}
}

@-moz-document domain("tweetdeck.twitter.com") {
.media-img:hover {
    width: auto !important;
    height: auto !important;
    max-width: 100% !important;
    max-height: none !important;
}
.media-img {
    margin-bottom: 5em !important;
}
.mdl.s-full,
.med-tray {
    width: 100% !important;
    max-width: 100% !important;
}
.med-embeditem {
    overflow: auto !important;
    overflow-x: hidden !important;
    top: 5px !important;
    height: calc(100% - 10px) !important;
}
.med-tweet {
    background-color: rgba(0, 0, 0, 0.7) !important;
}

/* buttons */
.mdl-dismiss {
    right: 20px !important;
}
.mdl-media-prev .icon,
.mdl-media-next .icon {
    position: fixed !important;
    left: inherit !important;
}
.mdl-media-prev .icon {
    left: 13px !important;
}
.mdl-media-next .icon {
    right: 13px !important;
}
.med-origlink,
.med-flaglink {
    position: fixed !important;
}
.med-flaglink {
    right: 20px !important;
}
}