Anybody help. I'm new in K2

 

I have a problem & I don't know how to solved. ( I already have installed  the Spanish translation)In the gallery images:  How & Where I can Translate the text :

Examples:  Clik to open the image! -->Pulsar para ver imagen, & the texts when I see the pic, ie:NEXT --> PROX, etc.. 
Also pls How I can modify the picture size when I open the image & is very highMany Thanks & Sorry because I'm new & to be honest I don´t know work in joomla without K2 ( because is thinking for a business user.... like a some erp !!)Thanks again & Best Regards from Spain/Crispulo Martin