TwitterKit iOS 3.1.0: constantly hitting image size limit




I’m posting tweets from my iOS app via TwitterKit and I constantly hit image size limit:

[TwitterKit] Composer did fail: Error Domain=TwitterAPIErrorDomain Code=324 "Request failed: bad request (400)" UserInfo={NSLocalizedFailureReason=Twitter API error : Image file size must be <= 5242880 bytes (code 324), TWTRNetworkingStatusCode=400, NSErrorFailingURLKey=, NSLocalizedDescription=Request failed: bad request (400)}

Although the image I’m trying to attach is a jpeg 1024x1024px, ~100kb
Meanwhile, png representation of this image takes 5478182 bytes (that is larger than API limit)
So it seems to me that TwitterKit internally uploads images as PNGs (which is probably logical when we want to keep image transparency but is redundant in my case).

My questions: Is it possible to configure TwitterKit to upload JPEG representation of the image, instead of PNG? So I don’t consume user’s traffic and don’t hit API limit.
Or if my guess about PNG representation is not true - why I’m hitting API limit while uploading 100kb jpeg? How can I avoid it?