Look at this picture, i don´t understand why it say bizim terzi and not bizim terzimiz?

or for example there is an dizi named bizim okul. Why it´s not bizim okulumuz?

More examples:

Benim arabam vs benim araba

senin kardeşin vs senin kardeş

Bizim türklerimiz vs bizim türkler

What is difference between them?

Second type (which has no possessive suffix) is used in spoken language much more than the written language.

Dropping  possesive suffix 

Dropping possessive suffix in noun compounds is seen quite often in  daily language. 

 Bizim  evimiz --->  Our house  ---> Standart  form

Bizim  ev  ---> Our house   ---> Not standart but acceptable in daily use.

Bizim evi  gördün mü  ----> Have you seen our house ?

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Senin çayın  ---> Your  tea  

Senin çay  ---> Your tea 

Senin çay soğudu ---->  Your  tea´s gone cold.  ---> We hear sometimes people use this way by dropping the possessive suffix from the second noun. 

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Ayşe´nin  kalemi  yazmıyor ----> Ayşe´s  pen is not working.   ---> Standart 

Ayşe´nin  kalem  yazmıyor ----> Ayşe´s  pen is not working.  --->  Not standard but it is sometimes used in daily  Turkish.      

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