Queensland State Archives posted a photo:
The linking of May Day with Labour Day in Queensland began in Barcaldine on 1 May 1891, when striking shearers and bush workers marched through the streets. The strike was broken five days later on 6 May 1891, when the colonial administration, with the backing of the New South Wales and Queensland governments, ordered the arrest of the shearers’ leaders on a number of charges, including sedition and conspiracy. Thirteen ringleaders were found guilty of conspiracy on 20 May 1891 at Rockhampton, and sentenced to three years hard labour in the gaol on Saint Helena Island. The strike committee issued its final manifesto on 20 June 1891, calling for unionists to register on the electoral rolls.
Queensland State Archives, Digital Image ID 2770