Well I run and also have access to huge accounts totalling well over 15 million followers now and have been in the Twitter game for some time.
Text posts do better than images sometimes, it depends on what the text is. Some text motivational quotes get thousands of Retweets if it's relatable.
Some people tweet images, but just browsing on your timeline, you can't see the main part of the image because of the size of the image, this results in less people retweeting because they can't be bothered to click the tweet to see the full image.
So, a suggestion is to check how the image looks in your tweet.