All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad  is His slave and Messenger.
  is His slave and Messenger.
The preponderant opinion is that in oaths, what counts is the intention of the one swearing. A person may utter a general statement but intend something specific by it; thus, the intention specifies the general wording.
Accordingly, if your intention at the time of taking the oath was to refer only to certain videos or specific images, then your oath applies only to what you intended at that moment.
As for merely coming across the videos you swore not to watch, without deliberate intent, this does not constitute breaking the oath or require expiation, according to the preponderant opinion. This is because the act that counts as “watching” is that which is done intentionally and with continued attention, not something that appears accidentally before one quickly diverts his sight. Such instances fall under the category of unintentional mistakes, for which both the Quran and Sunnah indicate there is no blame.
An unintentional mistake refers to any word or deed that a Mukallaf (legally competent) person says or does without wilful intent or deliberate choice.
Ibn al-Qayyim  states in 'Iʿlam al-Muwaqqiʿin': “He only swore concerning actions that are within his control, while this matter lies beyond his ability. Therefore, what he did in such circumstances is not included in his oath, nor did he intend to prevent himself from it.” [End quote]
  states in 'Iʿlam al-Muwaqqiʿin': “He only swore concerning actions that are within his control, while this matter lies beyond his ability. Therefore, what he did in such circumstances is not included in his oath, nor did he intend to prevent himself from it.” [End quote]
Allah knows best.