How to do simple picture processing with Photoshop?

Run Photoshop software, open the picture, and then click the menu "Image-Image Size" to open the panel as shown:

Make sure that the Constraint Ratio below is marked with \/to limit the aspect ratio. Then enter a numerical value (pixel) in the width, which is generally 800, which can meet most requirements. Click "OK" button after input.

Finally, click "File-Save as web Format" to open the panel as shown in the figure (click the image to enlarge):

Select "JPEG" file format under the word "preset" on the right side of the panel and set the quality to "high" or "medium". At this point, the compressed image size will be displayed in the lower left of the panel. If it is less than 200KB, you can click the "Save" button at the top right of the panel and enter a file name to save.

If the size exceeds 200KB, you can set the quality lower, or click Image Size in the middle right of the panel, re-enter the width value, click the Apply button, and then check the file size. If it does not exceed 200KB, it can be saved.

Section 3: How to adjust the brightness, contrast and color of an image?

These functions are in the submenu under the menu "Layer-New Adjustment Layer", including: color scale, curve, color balance, brightness/contrast, hue/saturation, etc. You can try it yourself. After trying, if you want to return to the original image, you can open the menu "Window-History" (make sure to press "\/"before "History"), so that you can open the history panel as shown:

In the History panel, you can return to any step at will. Click Open to return to the state when you first opened the image.

Section IV: Introduction to Other Functions:

Rotate image: Open the menu "Image-Rotate Canvas" in turn, and you can rotate 180 degrees, 90 degrees clockwise (counterclockwise) or at any angle. It can also be flipped horizontally (vertically).

Turn a color image into black and white: Open the menu "Image-Mode-Grayscale" in turn.

Magic image: The computer can process the image very freely and change it like a magician. You can try all the commands in the menu "Filter", which may bring you unexpected surprises!

Enter text: Use the "T" text tool on the left panel (or directly press T on the keyboard) and click anywhere on the image to enter text. After entering the text, press and hold the CTRL key on the keyboard directly, and a box with six corners will appear. You can enlarge and reduce the text by dragging each small box. To change the font like in word, you must first select the text with the "T" text tool, and then change it in the text toolbar below the menu. Change color: Click the menu "Window-Swatches" in turn (make sure to add "\/"before "Swatches") and select the color you want in the Swatches panel. Then press ALT+ Delete to fill the text with color.