The best way to post your photos is by making your own User Gallery. To do this,
** I made a screencast that might help people better than the directions below.
1) Login(if you've already registered)
2) Click on the main menu link Photo Gallery
3) Click Create/Order My Albums (button above main gallery album list) Unless you feel like your photos are general enough in nature to be added to the general galleries, add them in your User Gallery. It's a better way to keep your photo collections for telling stories and associating particular photo narratives with you as a user. Plus, you'll retain control over them to delete, replace, edit, etc.
4) Once you've opened the Albums page, make sure the drop-down menu at the top has *My Gallery selected. Then, below the large text area in the center of the screen click New, highlight the words "New album" that aooear in the text box and replace with the name of your album, then click Apply Modifications. You have created an album for your use only. If you like to be well organized, you can create many albums. I make a new one for each major adventure or type of flight.
5) Upload your files by clicking the Upload File button in the main menu at the top right of the gallery page(Gallery Menu). Browse to your local image file by clicking Browse next to one of the numbered fields and click Continue. Be patient during this time and don't double-click the button. When it's finished, the page will change and it will ask you to categorize your images.
6) Categorize your images: Choose *<my album name> (whatever you named your new album.) Your user album that you created in Step 4 will be in the top of the list, and have a * next to it. All of your user albums are preceded by asterisks. You can put your photos in any of the main Type categories too, but an email is sent to me first telling me that uploaded images are waiting to be approved, and I will approve them before they go in. No approval is needed for your user gallery.
7) Now everyone can browse the user galleries and see your personal gallery.
User storage limits are 1000 MB (1GB), image file size must be smaller than 500K and less than 2200 pixels wide.
Read this How To on digital image resizing to make the most of your storage limits.
Read this How to on adding your images to forum posts as well.