Golden Rule of digital images.
Never overwrite the original file.
Even if it looks awful it contains higher quality data than anything you subsequently prise out of it. Protect it in one or more of the following ways.
Working on a copy of the picture file
This description is based on Paint Shop Pro. Whatever you use make sure the "undo" feature is available usually applied by ctrl-z.
Is the horizon level? Rotate the picture to get the horizon as .. er .. horizon-tal as possible. In Paint Shop Pro use the draw tool in single line mode to draw a line across the horizon. Before releasing the second point on the line check the angle in the status bar at the very bottom of the PSP window. Now undo the line you have just drawns (ctrl-z) and rotate the picture backwards by that angle.
Look for converging verticals. These might be door or window frames, wall corners, lamp columns. They converge if the camera was pointing slightly upward or downward. If the convergence is obvious and intrusive then use the deformation tool to pull the picture into a better shape. To enable the deformation tool, select all (ctrl-a) and promote to layer (shift-ctrl-p). Click the deformation tool and pull the corners horizontally to straighten up the verticals - with shift to skew parallelogram - with ctrl to mirror left and right deformation. To get out of deformation mode click on one of the selection tools.
Details lost in shadow? Wring the most detail from the main subject by adjusting the contrast of the picture. If faces are in shadow, increase brightness and reduce contrast even if it means background is less satisfactory.
Colour or b&w? If a colour photo looks drab it can be cheered up by a judicious increase in colour saturation.
Got the blues? Some films fade towards blue over the years. Whatever the trend you may be able to bring it back to the original colour balance and make the scene look a little warmer. A photo illuminated by ordinary bulbs may need the orange edge taking off. The colour balance tool will do that easily.
JPEG is the file type of choice for photographs on the web. The compression is 'lossy' in that it only approximates the original when it is reflated. If you did the same with a text file instead of the normal ZIP you would need to run the spell checker over it full time. Artifacts are the equivalent of typos.
Change the subject. It might be a pretty scene but we are here to see our mates and ourselves when we were in our prime. Crop mercilessly to show the people and a bit of their motorcycles.
Fit for the web. Photos need to be visible without scrolling on a screen size of 800 x 600. The biggest size in the LPMCC.net layout is 540 pixels wide by 405 pixels high. Resizing to reduce the physical size of the picture is the first and most useful way of reducing the file size and helping the page to open more quickly.
Sharp's the word. Drag out the last bit of detail using the Effects > Sharpen option.
Saving grace. Export the file as a JPEG at 40% compression. That is very high compression but for this size of picture the lossy artifacts should not be too bad. Save the file with a sensible name.Write the HTML tag next
Never overwrite your original image file.
Crop to the main image subject - usually people.