in tthe notes , It's stated that the shear flow will be varies lineraly prependicular to the direction of shear force , V . But , in the phooto, it shoed that the shear flow will be varies parabolically prependicular to the direction of shear force ... Which is correct ? the notes or the example in the photo ?
You're getting something mixed up in your head here.
The shear force is travelling in the vertical direction (up/down).
The segment perpendicular to that shear force is the horizontal component (left/ right) AKA the top and bottoms of the I beam. In this section the shear flow is linear on the drawing.
The centre section is going vertically, therefore it is parallel to the shear; and it shows the shear flow acting parabolically.
To summarize; both the notes and photo are correct; something in your interpretation was just misunderstood.