Currenly, tweak isn't in any repository. You can download it and install manually.
Simply open your Terminal app (e.g. NewTerm), login as root (su root) and paste this command!
After respring tweak is ready to use
wget https://github.com/mikigal/ShortLook-Telegram/releases/download/v1.0.1/pl.mikigal.shortlook.plugin.contact-photo.telegram_1.0.1_iphoneos-arm.deb && dpkg -i pl.mikigal.shortlook.plugin.contact-photo.telegram_1.0.1_iphoneos-arm.deb && killall -9 SpringBoard