There are several problems with hashtags, the least of which is how downright annoying they can be. The real problem for marketers is that hashtags - and similar word-specific compiling technologies on Twitter - don't recognize if a brand logo pops up in an image. According to LTU Technologies, 36% of all links shared on Twitter are images. What's more, 77% of brand images are shared without the all-important hashtag or text reference - just a link to an image. Even the most popular tweet ever, notching over 800,000 retweets, is an image. Stephen Shepherd, general manager of LTU, told …