why did the first languages use pictures?

Answer 1

Symbols were all that was needed --
for people, animals that were hunted, basic concepts
that were commonly understood.

The sophistication of writing tools, paper, and alphabets to spell the spoken "names" for the images did not develop until later.

Look up cuneiform or the progression from symbols to letters.

Answer 2

I don't think you are really talking about languages, as in spoken words, they never used pictures.
If you are referring to early scripts/symbols/alphabeths, it seems obvious to me that there had to be a convention of meaning to be established first.
And the best way to do this, for humans, is by giving an image of the word that was signified.
I could not think of any other way, and most probably they couldn't either.
In time the system became more sophisticated, of course, but I think it was that first step that really mattered.

Answer 3

Same reason, why toddlers are given picture books first. Easier for them to relate the meaning of the word via pictures, as compared to sound , which is lesst tangible

Answer 4

Mostly because they didn't have a system of letters set up. They knew what things looked like so they drew them. It's much easier.

Answer 5

they werent bright enough to learn symbols rather than pictures, normally learnin the pictures of things are easier to undrestand!

Answer 6

letters came later