For your first example:
It's a book (of) pictures.
The "of" here is almost completely inaudible. It sounds to me like it's pronounced as an unvoiced schwa sound, and it's impossible to distinguish it from the release of the /k/ sound.
But there are two ways to tell that the speaker isn't saying "it's a book pictures". First is the fact that the /k/ is released; if the speaker were saying "it's a book pictures", he would probably pronounce the /k/ as an unreleased stop. Second is the fact that "it's a book pictures" simply isn't a likely phrase in English.
For your second example:
It's not finish**(ed)** yet.
Once again, the /t/ here is really hard to hear. I'm not sure if the speaker is actually is actually stopping the air flow at all!
But still, what I hear is different from what it would sound like if the speaker were saying "finish yet". It sounds to me like the /ʃ/ sound in "finish" is shortened, and followed by a "constricted" sound, before the /j/ in "yet" begins. That "constricted" sound is how the /t/ is being spoken, even if it's not actually [t].
If the speaker were saying "finish yet", then this "constricted" sound would be gone, and the /ʃ/ sound would be longer.
For your third example:
I'(d) like that.
This time, I think there really is a [d] sound there, but it may be hard to hear because there's very little evidence that it's there: it's spoken very quickly and it has no audible release.
But what I can hear is that the sound gets noticeably quieter after the "I" of "I'd" is pronounced, and then it gets louder again as the "l" of "like" begins. If the speaker were saying "I like that", then the loudness would stay mostly even as the vowel "I" transitions into the consonant /l/. The vowel would probably also be a little bit longer.
For this one, the "quiet spot" in between the "I" sound and the /l/ is clearly visible in the spectrogram.