Hi Siri. I use photoshop for editing images, altering colours and resizing etc. Note, if you create a document / image and find an image using google or what ever means too small and try to upsize to fit the alignment of the full size of the document it will distort. You should find images that are bigger than the current size of the document, so that if you need to resize the document itself it can be dont without loss of quality to the overall image.
Download and install the photoshop trial, its free for 30 days , I have the CS3 version (a year or so old, but i prefer it as it runs faster on a slower low spec pc / laptop) Memory is key, if your working with huge images and need to resize them down to edit I suggest you have more than 1gb memory. I have 1gb memory on my laptop and its a nightmare to load, can take me up to 2-3 hours to complete a set of banners. Working on my pc I could complete the same in around 1 to 1.30 hrs as it has 4 gb memory and doesnt halt so much in the process of loading and editing the images.
The banners I can have a lot of layers, the layers consist of many different images all combined and/or editing into one collage if you like.. I blend the "collages" in, also using the "rubber" or "smudge/sharp" brushes to create different effects. If you want try and get to basics with using the program, select the pictures you like with the image size correctly input and I could go from there with the blends etc. Or you could try it yourself, I wouldnt say its hard but it take a lot of practice.. There are certain blur/etc filters i use for the colour effects, I also use effects and stlyes for the words I create along with certain gradients.
Tips I would use:
To make the images smaller without loosing quality providing the images are quite big to begin with, hold CTRL then press T which outlines or selects the image and allows it to be "free transformed" you then hold CTRL + ALT whilst moving the little squares each corner of the images and drag smaller. This will keep the image in proporation to its size, if you resize it to the exact dimesions of the size of the document then you will get the distorted look. As im not at home at the moment the shortcut could be wrong, it could be hold left-shift + alt after pressing CTRL + T.. Im sure its the first shortcut, the second however allows you to distort it to a different kind of 3D look, selecting one of the corners (using the second shortcut) and dragging will create this effect. There are mainly tutorials out there too, i dont use tutorials myself but in the past they have been good for certain effects.. Good-Tutorials.com is a good one to start with, search for the effects you'd like to create with photoshop and it has many guided tuts for beginners new to the program. It has took me many years to learn how to use the program to good effect, I prefer to learn by myself and through use of memory. I have used various sites for tips when I have been stuck but getting to know the program and using it a lot will heel good results dependent on what your trying to achieve. As with all things I always prefer to learn myself, as with different forms of coding HTML, XML etc its good to know a little but you will not need to learn any kind of coding if your just creating a basic banner.. Also another good tip, always save and make a backup so that if you slip up you can recover the document to where it was previously saved, there is a command that "undoes" the last command or thing you did to the picture and it is CTRL + ALT + Z remember though it can only undo so much probably around 10 commands at most, after this point it will not remember or undo and instead it will keep redoing. You'll understand once you get used to it.Basics: Once photoshop is downloaded and installed.
Create a new document: go to file, new and it should pop up with a diaglog box such as this:
please note this is not my image, its just a general picture used as a point of reference (from google)
Make sure you select pixels on the right and type in the specific dimensions: 767 Width and 135 Height would create the size you talk about.
You will now be presented with a white background on this newly created document. Here is where you drag images from your source, edit and fit them within the "banner" dimension. Use the blends on the drop down menu for the layers to the left to create certain effects such as light and dark overlays etc, use the different tools and get to know the different tools as that will become indispensable to your quest
Let me know if this information is good enough, for extra tips you could ask me for my ICQ, Pm me if its only a small tip or email. I dont mind helping.