Like other contestants, Thomas has taken part in many Big Brother spin-off programmes, including BBLB and Big Brother's Big Mouth. She also co-presented with other housemates for T4.
She has also made numerous personal appearances in various programmes, including: E4's horror Dead Set, written by Charlie Brooker; the BBC Three programme Wags, Kids and World Cup Dreams, and Celebrity Coach Trip partnered with friend Bianca Gascoigne.
A fluent Welsh language speaker, she has appeared on various S4C programmes, including Uned 5, Wedi 3, Wedi 7, Jonathan Show and Bwrw Bar. She had her own show along with Glyn from Big Brother called Glyn and Imogen: A Year On. She also had a cameo role in the famous Welsh soap Pobol y Cwm. An S4C documentary series called Salon Imogen followed her setting up a nail bar in Cardiff. She closed the shop months later after wanting to pursue her career as a model.
In July 2011 she had got a job as a presenter during a spot on This Morning.
Selected as a housemate in the seventh series of the Channel 4 TV series, Big Brother, up to week 5, Thomas was not allowed to participate in nominations. In week 1 she was in the Big Brotherhood, and there were no nominations. In weeks 2 and 3, she was banned from nominating for discussing nominations. In week 4, only Susie was permitted to nominate, and in week 5, as punishment for yet again discussing nominations she was forced (along with 4 other rule breakers) to nominate one fellow rule breaker in front of the group. On Day 84, Imogen moved with fellow nominee Richard into the House Next Door, where she remained until she was evicted on Day 86 with 62% of the public vote.