I don't know if this varies depending on the visa category (I don't see yours mentioned), but at least for Tier 1 (General) the guidance clearly specifies that payslips must be "original & formal" (i.e. not electronic), and if they are electronic, they must be accompanied by an employer letter confirming that the electronic payslips are authentic:
from Appendix A - Attributes:
(1) original formal payslips issued by the employer and showing the employer’s name, or
(2) accompanied by a letter from the applicant's employer, on the employer’s headed paper and signed by a senior official, confirming the payslips are authentic
Apologies in advance if this response isn't relevant to your specific category.