In order to post a photo you need to issue API request to sendPhoto method, rather than sendMessage (as in example you referred). See API docs for more details. Note that in sendPhoto description parameter is called "caption", not "text".
I'm not sure whether IFTTT is able to send file content using multipart/form-data which is required by Telegram API. I'm pretty sure it should be able to.
PS: I'm the creator of CelebrityGirls channel but it doesn't rely on IFTTT or any similar services.