For Those Who Have Connections/Interest In Ireland: The National Archives Of Ireland
Link: National Archives: Census of Ireland 1901/1911
The census data for 1901 and 1911 are online as well as other resources accessible at the same site:
Ireland in the early 20th century:
Or you could simply browse the census data:
The photographic images in the galleries attached to each chapter should be clicked on to expand. You can then view them with explanatory captions and credits. Below each image you will find the option to view as a full-size jpg. image, or as a full-size image in PDF, with an option to download Acrobat Reader, a free tool which will allow you to view and manipulate the image.
PDF format allows you to zoom in and out on aspects of the image, by using the + and – tools at the top of the page, and to save and print the image.
All of these images are copyright to their repositories or custodians, and may not be reproduced without permission from them.