This book contains the proceedings of the 12th International Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISIGRAPP 2017) which was organized and sponsored by the Institute for Systems and Technologies of Information, Control and Communication (INSTICC), in cooperation with ACM SIGGRAPH, AFIG and Eurographics. The proceedings here published demonstrate new and innovative solutions and highlight technical problems in each field that are challenging and worthwhile being disseminated to the interested research audiences. VISIGRAPP 2017 was organized to promote a discussion forum about the conference’s research topics between researchers, developers, manufacturers and end-users, and to establish guidelines in the development of more advanced solutions. We received a high number of paper submissions for this edition of VISIGRAPP, 400 in total, with contributions from all five continents. This attests to the success and global dimension of VISIGRAPP.