You're correct on the provenance of the photo, but perhaps you read a different nuance. The photo showed migrants being escorted by police to bring some order to the tens of thousands of people (again, largely young men, rather than the more vulnerable elderly, women and children) moving THROUGH safe countries in search of the places they wanted to end up - wealthier western nations.
Other photos around that time show the police escorting those people to the borders they wish to cross, rather than taking them somewhere safe and processing them.
There were hundreds of refugee camps to the south, west and east of Syria where they would have been safe and sheltered, but they wanted to come to predominantly white western nations to find safety - why do you think that might have been?
Again, what is positive about that photo?
The poster did not imply that most immigrants to the UK were brown, it clearly showed tens of thousands of brown people who wanted to travel to northern Europe; they had plenty of other options and chose white northern European countries which don’t match their culture or experience. It was rightly frowned upon when hundreds of white people travelled the world and fundamentally changed brown countries; why is it acceptable the other way? Or do we just have to put up with it because apparently we did it first?