The shed was painted by some of the volunteers at the Newtown Mass Vaccination Centre.
It includes cartoons of covid vaccines and a welcome in English and Welsh.
Aled Morgan, support services manager at the site for Powys Teaching Health Board, said having the volunteers at the centres was a massive help.
“All the volunteers want to be there, and they want to make a difference," se said.
"They have been paramount to the success of the operation.”
Mr Morgan said the volunteers deployed in the car park had been given a shed to provide weather protection and said of its redesign: “I think it looks brilliant and adds a bit of colourfulness to the whole thing.”
Amanda Willday, business support manager for the Newtown Mass Vaccination Centre, said the volunteers had wanted to create something that created a visual impact for people arriving, before they enter the building, and said the pink shed is proving to be a popular talking point.
She said volunteers have also played a crucial role in putting people at ease before having their vaccinations.
The volunteer organisation, PAVO, is recruiting more volunteers for the mass vaccination centres at Llanelwedd and Newtown.
All volunteers will complete a risk assessment, be DBS checked, and complete a small programme of basic training.
If you are interested, register on the Volunteering Wales website for Llanelwedd at powys.volunteering-wales.net/vk/volunteers/my_opportunities_info_ur.htm?pID=10170754 and Newtown at powys.volunteering-wales.net/vk/volunteers/my_opportunities_info_ur.htm?PID=10170738
"Once you have registered you must go back onto the link and apply for the opportunity. It will ask you for two references - name and email - and that will get you linked to the opportunity. Once you have registered, you will be sent an email detailing the next steps."
Help and support to register as a volunteer is available from PAVO. Email firstname.lastname@example.org or ring 01597 822191.