Do not put spaces between parameters. The other parameters are optional and can be placed in any order. Some infoboxes do not require the brackets. Keep parameters in lower case. The other parameters are:
Type
'thumb' / 'thumbnail' or 'frame'. This causes image to be displayed with specific formatting. "thumb" is normally preferred.
Location
'right', 'left', 'center' or 'none'. Determines placement of the image on the page. "Left" or "right" is the norm, but large panoramas or timelines can be displayed in the center.
Size
{width}px or {width}x{height}px (e.g. 50x40px, would limit width to 50 pixels and height to 40 pixels). Normally only one variable is used. Use common sense when determining the sizes; you can use the "Show preview" button if you need to. If thumb or thumbnail is chosen, size should normally be left out, so that the size defaults to the size set in a user's preferences.
alt=
(keep it lower case). This is the "alternate image" parameter used to describe the image for screenreaders or for people with low-vision. It should be more descriptive than the caption alone. Do not use this for another copy of the caption or of the article title, as the reader will already be aware of these.
Caption
Any element which cannot be identified as one of the above is automatically treated as caption text. It is traditional to put this last. The caption should identify what the image is, and ideally be a complete sentence that adds to the article by pointing out something a casual reader would not have noticed otherwise, or add information the pertains to the image. Full sentence or multi fragment captions require full stop punctuation.
If you have created a picture that is not already in Wikipedia's image collection on the Commons that you want to include in an article, you will need to upload it first. Bonus tip: Similar formatting is used to insert basic audio or basic video clips into articles.
In Firefox, the search box has a little pull down menu to allow you to choose which search engine it uses. Several popular search engines come included, but not Wikipedia. However, Firefox provides a page on their website listing more search engines you can add to that menu, including Wikipedia's search. To add Wikipedia, simply go here and click on Wikipedia in the list provided, and you are done. To activate it, pull-down the menu at the search box and click on Wikipedia there. Now you have a second Wikipedia search box. Unlike the search box in Wikipedia's sidebar, which disappears off the screen when you scroll down to read a long page, the Firefox search box always remains on the screen, ready to assist. (Keep in mind, typing Alt+F also places the cursor in the Wikipedia search box.)