Good find. I like how they are drawn and all handling their sickness differently. Not sure what that extra masculine looking Pinkie Pie is doing...
I don't know what the original drawing was, but this is the most informative comment, and it's by Wolfwood! Some keys are it involved all the characters, being sick. They are handing their sicknesses different, which is an odd thing to say. Is it showing them separately doing things with a cold? Pinkie Pie looks manly.
Search for tags involving the mane 6, Pinkie Pie, sick, etc.
I don't see anyone mentioning sneezing.