The secure and reliable transmission of digital files is blocked by platform-specific restrictions that restrict transmission of certain file types through these platforms. In this paper a robust and scalable framework to overcome such limitations by lossless conversion of arbitrary binary files into a sequence of grayscale PNG image subfiles is provided. The proposed technique is based on a structured bit-to–pixel mapping protocol in which each converted image contains at least one 96-bit metadata header. This header includes a unique file identifier of length 64 bits, which is obtained from the hash SHA-256 and contains an optional 32-bit sequence number to be used for cryptographic verification as well as proper sequencing of generated image files in reconstruction process of original file. This mechanism enables the perfect regeneration of the original file by combining subfiles at receiving end. Proposed framework provides a novel and dependable approach to file transmission in restricted digital environments. The proposed method takes an average processing rate of 3.13 s/MB for conversion of file to be transmitted into image subfile sequences and 2.59 s/MB for reconstruction of the original file at receiving end.